Don't need :group for defcustom

I just learned that it's not really needed when the defgroup and
defcustoms are all in the same file, as we do. The defcustoms use the
most recently declared defgroup.

Take advantage of that to reduce some "noise".

racket-custom.el

@@ -21,6 +21,9 @@
 (require 'sh-script) ;for sh-heredoc face
 (require 'comint) ;for comint-simple-send in racket-shell-or-terminal
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; racket group
+
 (defgroup racket nil
   "Modes for the Racket language."
   :group 'languages
@@ -42,8 +45,7 @@ non-nil `racket-program` property list value. See
 `racket-add-back-end'."
   :tag "Racket Program"
   :type '(file :must-match t)
-  :risky t
-  :group 'racket)
+  :risky t)
 
 (make-obsolete-variable 'racket-command-port nil "2020-04-25")
 
@@ -58,8 +60,7 @@ response. Instead most Racket Mode commands these days receive
 their response asychronously."
   :tag "Command Timeout"
   :type 'integer
-  :risky t
-  :group 'racket)
+  :risky t)
 
 (make-obsolete-variable 'racket-path-from-emacs-to-racket-function nil "2020-08-26")
 
@@ -75,8 +76,7 @@ Defaults to `racket-browse-url-using-temporary-file' on macOS and
 `browse-url' on other platforms."
   :tag "Browse URL Function"
   :type 'function
-  :risky t
-  :group 'racket)
+  :risky t)
 
 (defcustom racket-documentation-search-location
   "https://docs.racket-lang.org/search/index.html?q=%s"
@@ -94,8 +94,7 @@ and `racket-repl-documentation' should look for the search page.
   :tag "Documentation Search Location"
   :type '(choice (string :tag "URL")
                  (const :tag "Local" local))
-  :safe (lambda (val) (or (stringp val) (eq val 'local)))
-  :group 'racket)
+  :safe (lambda (val) (or (stringp val) (eq val 'local))))
 
 (defcustom racket-shell-or-terminal-function 'racket-shell
   "How `racket-racket' and `racket-raco-test' run commands.
@@ -112,10 +111,10 @@ Predefined choices include `racket-shell', `racket-term',
              racket-term
              racket-ansi-term
              racket-vterm)
-  :risky t
-  :group 'racket)
+  :risky t)
 
-;;; Xp Mode
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; racket-xp group
 
 (defgroup racket-xp nil
   "`racket-xp-mode' options"
@@ -129,8 +128,7 @@ Set to nil to disable automatic refresh and manually use `racket-xp-annotate'."
   :tag "Racket XP Mode After Change Refresh Delay"
   :type '(choice (integer :tag "Seconds")
                  (const :tag "Off" nil))
-  :safe #'integerp
-  :group 'racket-xp)
+  :safe #'integerp)
 
 (defcustom racket-xp-mode-lighter
   '(:eval (racket--xp-mode-lighter))
@@ -139,8 +137,7 @@ Set to nil to disable automatic refresh and manually use `racket-xp-annotate'."
 Set to nil to disable the mode line completely."
   :tag "Racket Xp Mode Lighter"
   :type 'sexp
-  :risky t
-  :group 'racket-xp)
+  :risky t)
 
 (defcustom racket-xp-highlight-unused-regexp "^[^_]"
   "Only give `racket-xp-unused-face' to unused bindings that match this regexp.
@@ -149,8 +146,7 @@ The default is to highlight identifiers that do not start with
 an underline, which is a common convention."
   :tag "Racket Xp Mode Do Not Highlight Unused Regexp"
   :type 'regexp
-  :safe #'stringp
-  :group 'racket-xp)
+  :safe #'stringp)
 
 (defcustom racket-xp-add-binding-faces nil
   "Have `racket-xp-mode' fontify binding identifier sites.
@@ -170,10 +166,10 @@ This has a visible effect only when there is /not/ also a
 \\='face property applied by the major mode's fontification."
   :tag "Racket Xp Mode Binding Font Lock Face Modes"
   :type '(repeat symbol)
-  :safe #'listp
-  :group 'racket-xp)
+  :safe #'listp)
 
-;;; Hash Lang
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; racket-hash-lang group
 
 (defgroup racket-hash-lang nil
   "`racket-hash-lang-mode' options"
@@ -214,10 +210,10 @@ String tokens use `font-lock-string-face'. Text tokens, e.g.
 Scribble text, use the face `default'"
   :tag "Hash Lang Token Face Association List"
   :type '(alist :key-type symbol :value-type face)
-  :safe #'listp
-  :group 'racket-hash-lang)
+  :safe #'listp)
 
-;;; REPL
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; racket-repl group
 
 (defgroup racket-repl nil
   "`racket-repl-mode' options"
@@ -248,8 +244,7 @@ necessary."
                  (const :tag "One REPL buffer for all project edit buffers" racket-repl-buffer-name-project)
                  (const :tag "One REPL buffer for each edit buffer" racket-repl-buffer-name-unique)
                  (function :tag "Other function"))
-  :risky t
-  :group 'racket-repl)
+  :risky t)
 
 (defcustom racket-submodules-to-run '((test) (main))
   "Extra submodules to run.
@@ -271,8 +266,7 @@ It is NOT used by commands that run one specific module, such as:
  - `racket-profile'"
   :tag "Submodules to Run"
   :type '(repeat (repeat :tag "Module path" symbol))
-  :safe #'listp
-  :group 'racket-repl)
+  :safe #'listp)
 
 (defcustom racket-memory-limit 2048
   "Terminate the Racket process if memory use exceeds this value in MB.
@@ -286,8 +280,7 @@ terminated upon the first garbage collection where memory exceeds
 the limit (maybe by a significant amount)."
   :tag "Memory Limit"
   :type 'integer
-  :safe #'integerp
-  :group 'racket-repl)
+  :safe #'integerp)
 
 (defcustom racket-error-context 'medium
   "The amount of context for error messages.
@@ -315,32 +308,28 @@ more-helpful error message."
   :type '(radio (const :tag "Low" low)
                 (const :tag "Medium (better context but slower)" medium)
                 (const :tag "High (best context but slowest)" high))
-  :risky t
-  :group 'racket-repl)
+  :risky t)
 
 (make-obsolete-variable 'racket-retry-as-skeleton nil "2020-02-26")
 
 (defcustom racket-repl-history-directory
   (locate-user-emacs-file (file-name-as-directory "racket-mode"))
   "Directory for `racket-repl-mode' history files."
   :tag "REPL History Directory"
-  :type 'file
-  :group 'racket-repl)
+  :type 'file)
 
 (defcustom racket-history-filter-regexp "\\`\\s *\\'"
   "Input matching this regexp are NOT saved on the history list.
 Default value is a regexp to ignore input that is all whitespace."
   :tag "History Filter Regexp"
   :type 'regexp
-  :safe #'stringp
-  :group 'racket-repl)
+  :safe #'stringp)
 
 (defcustom racket-images-inline t
   "Whether to display inline images in the REPL."
   :tag "Images Inline"
   :type 'boolean
-  :safe #'booleanp
-  :group 'racket-repl)
+  :safe #'booleanp)
 
 (defcustom racket-imagemagick-props nil
   "Use ImageMagick with these properties for REPL images.
@@ -361,31 +350,27 @@ pixels, supply (:max-width 500)."
              (:width integer)
              (:height integer)
              (:rotation float))
-  :risky t
-  :group 'racket-repl)
+  :risky t)
 
 (defcustom racket-images-keep-last 100
   "How many images to keep in the image cache."
   :tag "Images Keep Last"
   :type 'integer
-  :safe #'integerp
-  :group 'racket-repl)
+  :safe #'integerp)
 
 (defcustom racket-images-system-viewer (if (eq system-type 'darwin)
                                            "open"
                                          "display")
   "The image viewer program to use for `racket-view-image'."
   :tag "Images System Viewer"
   :type 'string
-  :risky t
-  :group 'racket-repl)
+  :risky t)
 
 (defcustom racket-pretty-print t
   "Use pretty-print instead of print in REPL?"
   :tag "Pretty Print"
   :type 'boolean
-  :safe #'booleanp
-  :group 'racket-repl)
+  :safe #'booleanp)
 
 (defcustom racket-use-repl-submit-predicate nil
   "Should `racket-repl-submit' use a drracket:submit-predicate?
@@ -395,8 +380,7 @@ language syntax is not s-expressions. When t `racket-repl-submit'
 will use this to decide whether to submit your input, yet."
   :tag "Use REPL Submit Predicate"
   :type 'boolean
-  :safe #'booleanp
-  :group 'racket-repl)
+  :safe #'booleanp)
 
 (defcustom racket-before-run-hook nil
   "Normal hook done before various Racket Mode run commands.
@@ -410,8 +394,7 @@ instead needs the `racket-repl-mode' buffer, it should get that
 from the variable `racket-repl-buffer-name'."
   :tag "Before Run Hook"
   :type 'hook
-  :risky t
-  :group 'racket-repl)
+  :risky t)
 
 (defcustom racket-after-run-hook nil
   "Normal hook done after various Racket Mode run commands.
@@ -425,18 +408,17 @@ instead needs the `racket-repl-mode' buffer, it should get that
 from the variable `racket-repl-buffer-name'."
   :tag "After Run Hook"
   :type 'hook
-  :risky t
-  :group 'racket-repl)
+  :risky t)
 
 (defcustom racket-repl-command-file
   (expand-file-name "repl.rkt"
                     (locate-user-emacs-file (file-name-as-directory "racket-mode")))
   "Name of the file used by `racket-repl'."
   :tag "REPL Command File"
-  :type 'file
-  :group 'racket-repl)
+  :type 'file)
 
-;;; Other
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; racket-other group
 
 (defgroup racket-other nil
   "Other Options"
@@ -450,8 +432,7 @@ This is indirectly disabled if `racket-indent-sequence-depth' is 0.
 This is safe to set as a file-local variable."
   :tag "Indent Curly As Sequence"
   :type 'boolean
-  :safe #'booleanp
-  :group 'racket-other)
+  :safe #'booleanp)
 
 (defcustom racket-indent-sequence-depth 0
   "To what depth should `racket-indent-line' search.
@@ -465,8 +446,7 @@ indentation noticeably slower. This is safe to set as a
 file-local variable."
   :tag "Indent Sequence Depth"
   :type 'integer
-  :safe #'integerp
-  :group 'racket-other)
+  :safe #'integerp)
 
 (defcustom racket-pretty-lambda nil
   "Display lambda keywords using λ. This is DEPRECATED.
@@ -475,8 +455,7 @@ Instead use `prettify-symbols-mode' in newer verisons of Emacs,
 or, use `racket-insert-lambda' to insert actual λ characters."
   :tag "Pretty Lambda"
   :type 'boolean
-  :safe #'booleanp
-  :group 'racket-other)
+  :safe #'booleanp)
 
 (defcustom racket-smart-open-bracket-enable nil
   "This variable is obsolete and has no effect.
@@ -486,8 +465,7 @@ Instead of using this variable, you may bind the `[` key to the
 and/or `racket-repl-mode-map' keymaps."
   :tag "Smart Open Bracket Enable"
   :type 'boolean
-  :safe #'booleanp
-  :group 'racket-other)
+  :safe #'booleanp)
 
 (defcustom racket-module-forms
   (rx (syntax ?\()
@@ -499,8 +477,7 @@ Affects what `beginning-of-defun' will move to. This is safe to
 set as a file-local variable."
   :tag "Top Level Forms"
   :type 'string
-  :safe #'stringp
-  :group 'racket-other)
+  :safe #'stringp)
 
 (defcustom racket-logger-config
   '((cm-accomplice           . warning)
@@ -537,8 +514,7 @@ like \"debug\" and not get overhwelmed by these noisy topics."
   :set (lambda (var val)
          (set-default var val)
          (when (fboundp 'racket--logger-activate-config)
-           (racket--logger-activate-config)))
-  :group 'racket-other)
+           (racket--logger-activate-config))))
 
 (defcustom racket-show-functions
   (list 'racket-show-pseudo-tooltip)
@@ -575,8 +551,7 @@ ignore POS. Examples: `racket-show-echo-area' and
              racket-show-echo-area
              racket-show-header-line
              racket-show-pos-tip)
-  :risky t
-  :group 'racket-other)
+  :risky t)
 
 (defcustom racket-expand-hiding 'standard
   "The macro hiding policy for commands like `racket-expand-file'."
@@ -614,10 +589,10 @@ ignore POS. Examples: `racket-show-echo-area' and
                                (list :tag "phase>=?"
                                      (const phase>=?)
                                      (natnum :tag "natural number"))
-                               (sexp :tag "sexp"))))))
-  :group 'racket-other)
+                               (sexp :tag "sexp")))))))
 
-;;; Faces
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; racket-faces group
 
 (defgroup racket-faces nil
   "Racket Faces"
@@ -631,8 +606,7 @@ ignore POS. Examples: `racket-show-echo-area' and
      (defface ,id
        ,facespec
        ,docstr
-       :tag ,tag
-       :group 'racket-faces)))
+       :tag ,tag)))
 
 (defface-racket racket-xp-def-face
   '((t (:inherit match :underline (:style line))))