[cwctype.syn] Update to refer to C23 7.31

Author: frederick-vs-ja

source/text.tex

@@ -13088,7 +13088,7 @@
 The contents and meaning of the header \libheaderdef{cwctype}
 are the same as the C standard library header \libheader{wctype.h}.
 
-\xrefc{7.30}
+\xrefc{7.31}
 
 \rSec2[cwchar.syn]{Header \tcode{<cwchar>} synopsis}