* lisp/emacs-lisp/easy-mmode.el (define-minor-mode): Rely on the
`defcustom`s own defaulting for the :group.
* lisp/display-fill-column-indicator.el
(global-display-fill-column-indicator-mode): Remove now redundant :group.
* lisp/cus-dep.el (custom--get-def): New function.
(custom-make-dependencies): Use it.
(global-display-fill-column-indicator-mode): Specify the implicit
defustom's group explicitly.
* lisp/cus-dep.el (custom-make-dependencies): Also look at
define(-globalized)-minor-mode since it can also define custom vars.
* src/xdisp.c (syms_of_xdisp): Add reference to manual in
documentation strings for variables related to fill column indicators.
* lisp/display-fill-column-indicator.el (display-fill-column-indicator)
(display-fill-column-indicator-mode): Add reference to manual.
Restore lines saying "Maintainer: emacs-devel@gnu.org" when there is
no special maintainer for a file. Although this wasn't documented
it was common practice and removing the lines didn't have consensus.
*lisp/display-fill-column-indicator.el: Fixed character selection for
the indicator based in the current faces. Extended condition to set
display-fill-column-indicator-character in graphical displays.
*src/xdisp.c: Fixed some long lines.
