Handling of left/right single quotation marks

[whxvd]

For the following function describe-function creates a hyperlink for the occurence of kill-ring in left and right single quotes, whereas helpful-function does not:

(defun f ()
  "Docstring mentioning variable ‘kill-ring’ with left and
right single quotes, instead of mentioning `kill-ring' with grave
accent and apostrophe."
  nil)

The Emacs Lisp manual states:

Some previous versions of this section recommended using the non-ASCII single quotation marks directly in doc strings, but this is now discouraged, since that leads to broken help string displays on terminals that don’t support displaying those characters.

So I suppose that using left and right single quotes instead of grave accent and apostrophe in general is supported by Emacs, although discouraged nowadays. Ideally helpful would support that, too.