Re: master ed2b0bd: New faces in xref (bug#23179)

[Robert Pluim <rpluim@gmail.com>]

>>>>> On Mon, 15 Apr 2019 17:34:13 +0300, Eli Zaretskii <eliz@gnu.org> said:

    >> From: Robert Pluim <rpluim@gmail.com> Date: Mon, 15 Apr 2019
    >> 10:27:45 +0200 Cc: emacs-devel@gnu.org
    >> 
    Juri> I see no other related faces (compilation/grep) mentioned
    Juri> neither in NEWS nor in the manual.
    >> 
    >> True. Thatʼs arguably a deficiency in the manual.

    Eli> I tend to agree.  Feel free to document at least the more
    Eli> important ones ('error', 'warning').

grep doesnʼt have any faces that can be customized (at least not for
the output of grep. How about the following for compilation-mode:

diff --git a/doc/emacs/building.texi b/doc/emacs/building.texi
index 78d07b8d39..fa4c7f0e20 100644
--- a/doc/emacs/building.texi
+++ b/doc/emacs/building.texi
@@ -151,6 +151,23 @@ Compilation Mode
 the error message in a separate window.  The locus is the specific
 position in a file where that error occurred.
 
+@cindex compilation mode faces
+@cindex compilation mode appearance
+@vindex compilation-error-face
+@vindex compilation-error
+@vindex compilation-warning-face
+@vindex compilation-warning
+  The appearance of the @file{*compilation*} buffer can be controlled
+by customizing the faces which are used to highlight parts of the
+@file{*compilation*} buffer, e.g. @code{compilation-error} or
+@code{compilation-warning}, for error and warning messages
+respectively.  Note that since those faces inherit from the
+@code{error} and @code{warning} faces, it is also possible to
+customize the parent face directly instead.
+
+  Use @w{@kbd{M-x customize-group RET compilation}} to see the entire
+list of customization variables and faces.
+
 @findex compile-goto-error
 @vindex compilation-auto-jump-to-first-error
   If you change the variable