Fix bug #7576 with lack of index entries for character syntax.

 custom.texi (Init Syntax): Add index entries for "character syntax".

doc/emacs/ChangeLog

+2010-12-11  Eli Zaretskii  <eliz@gnu.org>
+
+	* custom.texi (Init Syntax): Add index entries for "character syntax".
+	(Bug#7576)
+
 2010-12-11  Karel Klíč  <kklic@redhat.com>
 
 	* text.texi (HTML Mode): Small fixes.  (Bug#7607)

doc/emacs/custom.texi

@@ -2234,6 +2234,8 @@ a Meta character, as in @samp{\M-a} for @kbd{Meta-A} or @samp{\M-\C-a} for
 non-@acronym{ASCII} in your init file.
 
 @item Characters:
+@cindex Lisp character syntax
+@cindex character syntax
 Lisp character constant syntax consists of a @samp{?} followed by
 either a character or an escape sequence starting with @samp{\}.
 Examples: @code{?x}, @code{?\n}, @code{?\"}, @code{?\)}.  Note that
@@ -2250,6 +2252,7 @@ keys which send non-@acronym{ASCII} characters.
 @code{nil} stands for `false'.
 
 @item Other Lisp objects:
+@cindex Lisp object syntax
 Write a single-quote (@code{'}) followed by the Lisp object you want.
 @end table