[fs.path.type.cvt] Fix cross-reference for execution wide-character set

Author: jensmaurer

source/iostreams.tex

@@ -13167,7 +13167,7 @@
 for pathnames\iref{fs.class.path}.
 The \defn{native encoding} for wide character strings is
 the implementation-defined execution
-wide-character set encoding\iref{lex.charset}.
+wide-character set encoding\iref{character.seq}.
 
 \pnum
 For member function arguments that take character sequences representing