[locale.ctype.members] Add missing parameter name

Author: cpplearner

source/locales.tex

@@ -1096,7 +1096,7 @@
 
 \indexlibrarymember{ctype}{toupper}%
 \begin{itemdecl}
-charT        toupper(charT) const;
+charT        toupper(charT c) const;
 const charT* toupper(charT* low, const charT* high) const;
 \end{itemdecl}