There was recently a question on the gnu-emacs-help list from someone
trying to customize the faces used in syntax highlighting C mode. He
looked in C mode customization group but could not find it.
Maybe it would be a good idea to have a link to the faces customization
from each mode customization group? (If that is possible in a simple way?)
One solution is to add the parent group `font-lock-highlighting-faces'
to all groups of modes that support font-lock. But this has one negative
effect: the `group' link is two-directional, so the customization group
`font-lock-highlighting-faces' will display too many children links
to all such groups.
A better solution is to implement a new one-directional link to another
customization group. Currently `:link' supports four link types, and a
new link type could have the name `custom-group'. It could create a
one-directional link in the customization buffer leading to the specified
group, e.g.:
(defgroup c nil
"Support for the C language and related languages."
:link '(custom-manual "(ccmode)") ;; this is already existing link
:link '(custom-group font-lock-highlighting-faces) ;; a new link type
:group 'languages)