master 40dcf9c2ab 4/5: read-multiple-choice: Display "SPC" instead of " "

[Eli Zaretskii <eliz@gnu.org>]

> branch: master
> commit 40dcf9c2abd62425e599f30548dc53fa58fe2202
> Author: Stefan Kangas <stefan@marxist.se>
> Commit: Stefan Kangas <stefan@marxist.se>
> 
>     read-multiple-choice: Display "SPC" instead of " "
>     
>     * lisp/emacs-lisp/rmc.el (rmc--add-key-description): Improve display
>     of the keys TAB, RET, SPC, DEL, and ESC.  This fixes a bug where " "
>     was highlighted in the description in a confusing way.
>     * test/lisp/emacs-lisp/rmc-tests.el
>     (test-rmc--add-key-description)
>     (test-rmc--add-key-description/with-attributes): Update tests for the
>     above change.

I don't think I like the result of this changeset.  Now SPC is
displayed as [SPC], in brackets, for a reason I cannot understand.
Those brackets get in the way, especially if the Help buffer is
already shown, because there the keys are shown as they should be:
without any brackets.

This affects novice.el, which is for newbies, and so the instructions
cannot be confusing.

Why is it a good idea to show some of the responses in brackets?  I
say let's remove the brackets altogether, they are not needed,
especially since the keys are already in a special face.  Too many
features at once are not necessarily a Good Thing.