bug#47529: [External] : bug#47529: Make quoted entities stand out more in info

[Drew Adams <drew.adams@oracle.com>]

> This has come up several times over the years.
> It never goes anywhere. Eg six-year old open reports:
> https://urldefense.com/v3/__https://debbugs.gnu.org/20721__;!!GqivPVa7Brio!NL
> Gc7PBOr5pJdigXPipQEbGpL4AeTn3gDgkFGadjZOnV49HmdKDSCasujFhT1zEs$
> https://urldefense.com/v3/__https://debbugs.gnu.org/18077__;!!GqivPVa7Brio!NL
> Gc7PBOr5pJdigXPipQEbGpL4AeTn3gDgkFGadjZOnV49HmdKDSCasujHT9fwTo$

Yup.

FWIW, in info+.el I use this for quoted names:

(defface info-quoted-name               ; For '...' and `...'
  ;; But see Emacs bug #44316.  If that gets fixed then
  ;; maybe revisit this default definition somehow.
  '((((background dark))
     (:inherit info-fixed-pitch :foreground "#6B6BFFFF2C2C")) ; ~ bright green
    (((background light))
     (:inherit info-fixed-pitch :foreground "DarkViolet"))
    (t (:foreground "yellow")))
  "Face for quoted names ('...' or `...') in `info'."
  :group 'Info-Plus :group 'faces)

And this is `info-fixed-pitch', which `info-quoted-name' inherits from:

(defface info-fixed-pitch
  `((t (:inherit fixed-pitch
                 ,@(let ((family
                          (catch 'info-fixed-pitch
                            (dolist (fam  info-good-fixed-pitch-font-families)
                              (when (member fam (font-family-list))
                                (throw 'info-fixed-pitch fam))))))
                     (and family `(:family ,family))))))
  "Fixed-pitch face for Info.
The default value inherits from face `fixed-pitch'.  And if you have a
font family listed in variable `info-good-fixed-pitch-font-families',
then the face attributes of the first one you have listed there are
merged with those of face `fixed-pitch'.

By default, face `info-fixed-pitch' is inherited by faces
`info-custom-delimited',`info-double-quoted-name',
`info-isolated-quote', `info-quoted-name', `info-reference-item', and
`info-string'."
  :group 'Info-Plus :group 'faces)