Support (locale-info 'paper) on MS-Windows

Support (locale-info 'paper) on MS-Windows

* src/w32proc.c (LOCALE_IPAPERSIZE): Define if undefined.
(nl_langinfo): Support _NL_PAPER_WIDTH and _NL_PAPER_HEIGHT
like glibc does.
* src/fns.c (Flocale_info): Update the doc string.

* nt/inc/langinfo.h: Add _NL_PAPER_WIDTH and _NL_PAPER_HEIGHT
to the enumeration.
(_NL_PAPER_WIDTH, _NL_PAPER_HEIGHT): Define namesake macros.
* nt/mingw-cfg.site (emacs_cv_langinfo__nl_paper_width): Set
to 'yes'.

* doc/lispref/nonascii.texi (Locales): Update the
documentation of 'locale-info' for the argument of 'paper'.

* etc/NEWS: Update the locale-info entry.