[locale.ctype.virtuals] Fix a decade-old typo

[cpplearner]

This sentence comes from LWG 379, but it seems that there's a mistake when applying the proposed resolution to the draft standard: the proposed resolution says "For any named ctype category with a ctype<char> facet ctc", but the draft standard says "For any named ctype category with a ctype<charT> facet ctc".

[jensmaurer]

Seems a correct change, based on LWG379.

@jwakely ?

[cpplearner]

ping @jwakely

[jwakely]

Isn't the entire subject of LWG379 that the standard says charT and should say char? So if applying the issue failed to make that change, what did it do, just add a comma? Maybe the editor misread the note "[Kona: Minor edit. Added a comma after the M for clarity.]" as saying that was the required fix.

[jwakely]

Ah it also changed ctw to ctc

[jwakely]

I've convinced my self that this change (as originally proposed by LWG379) is correct. It's strange that the original "typo" corrected by LWG379 also involved the name "ctw" which does strongly suggest that a ctype facet for Wide characters was intended, in contrast to do_narrow where it was always ctype<char> and ctc. If it was just a typo, you would not have expected the name "ctw" to also be a typo.

But since the argument to ctw.is(M, c) is a char it does make sense that ctype<charT> ctw was supposed to be ctype<char> ctc all along.