fix: help text as per new feats in #633 (#991)

help.txt

@@ -32,11 +32,16 @@ asdf where <name> [<version>]           Display install path for an installed
                                         or current version
 asdf which <command>                    Display the path to an executable
 asdf local <name> <version>             Set the package local version
+asdf local <name> latest[:<version>]    Set the package local version to the
+                                        latest provided version
 asdf global <name> <version>            Set the package global version
+asdf global <name> latest[:<version>]   Set the package local version to the
+                                        latest provided version
 asdf shell <name> <version>             Set the package version to
                                         `ASDF_${LANG}_VERSION` in the current shell
 asdf latest <name> [<version>]          Show latest stable version of a package
-asdf list <name>                        List installed versions of a package
+asdf list <name> [version]              List installed versions of a package and
+                                        optionally filter the versions
 asdf list all <name> [<version>]        List all versions of a package and
                                         optionally filter the returned versions
 asdf help <name> [<version>]            Output documentation for plugin and tool