references the symbol. This is usually a face, but can be any symbol
referenced by an element of the @code{font-lock-keywords} list. The
symbol can contain wildcards: @code{*} matches any string in the
-symbol'ss name, @code{?} matches a single character, and
+symbol's name, @code{?} matches a single character, and
@code{[@var{char-set}]}, where @var{char-set} is a string of one or
more characters, matches a single character from the set.