* libc/stdio/swprintf.c (_swprintf_r, swprintf):

	* libc/stdio/swprintf.c (_swprintf_r, swprintf):
	correct how terminating L'\0' is added;
	change return to match standard for when output does not fit;
	some corrections and enhancements to the docs.
	* libc/stdio/vswprintf.c (_vswprintf_r):  ditto, except for docs.
	* libc/stdio/vfwprintf.c:  some corrections to the docs and some
	enhancements to comments.  (No code changes.)
	* libc/time/strftime.c:  Correct some problems that made wcsftime()
	not work correctly:  work properly with swprintf returns that are
	different from snprintf returns, correct test vector lengths for
	when sizeof(wchar_t) > 1.
	* libc/stdio/sprintf.c:  Some documentation and comment corrections and
	enhancements to match those done to swprintf.c.