Improve documentation of glyphless-character display

* doc/emacs/display.texi (Text Display): Document and index the
'glyphless-char' face.

diff --git a/doc/emacs/display.texi b/doc/emacs/display.texi
index e3b24033a1ae63b1956984e1fb4b488f4c492e5d..c8987c279c5cb3377ac4332fbabc9af9e2122a83 100644 (file)
--- a/doc/emacs/display.texi
+++ b/doc/emacs/display.texi
@@ -1476,15 +1476,18 @@ elisp, The Emacs Lisp Reference Manual}.
 
 @cindex glyphless characters
 @cindex characters with no font glyphs
+@cindex glyphless-char face
   On graphical displays, some characters may have no glyphs in any of
 the fonts available to Emacs.  These @dfn{glyphless characters} are
 normally displayed as boxes containing the hexadecimal character code.
 Similarly, on text terminals, characters that cannot be displayed
 using the terminal encoding (@pxref{Terminal Coding}) are normally
 displayed as question signs.  You can control the display method by
-customizing the variable @code{glyphless-char-display-control}.
-@xref{Glyphless Chars,, Glyphless Character Display, elisp, The Emacs
-Lisp Reference Manual}, for details.
+customizing the variable @code{glyphless-char-display-control}.  You
+can also customize the @code{glyphless-char} face to make these
+characters more prominent on display.  @xref{Glyphless Chars,,
+Glyphless Character Display, elisp, The Emacs Lisp Reference Manual},
+for details.
 
 @cindex curly quotes
 @cindex curved quotes