documentation bugs

[Dave Kemper]

I've found a couple errors in groff's info pages, described below.  I can open 
a bug tracker item for these if you prefer, but they should be simple to fix 
and may not require that overhead.

For each error, I've supplied a command that shows the text where the error is, 
followed by a short description of the problem with that segment.  These 
commands all work against the latest version of doc/groff.texi from git.

$ fgrep -A28 'item latin-1' doc/groff.texi

Note the latin-1 and latin-2 sections consistently use "latin-1" and "latin-2" 
throughout their respective blocks, but the latin-5 section has elements 
referring to itself as both "latin-2" and "latin9".

$ fgrep -A4 '{ds}, and @code{as}' doc/groff.texi

This block says "string diversion" where it seems to mean only "string."  Also, 
the phrase "together with its variants" ought to be "together with their 
variants," since most if not all of the cited requests have variants.

$ fgrep -A1 '(this is, using' doc/groff.texi

Since the caller needn't be a macro, it seems this should say "from the caller" 
rather than "from the calling macro."

Also, the English idiom is "that is," not "this is."  This nonstandard phrase 
also appears a few other times throughout the info manual.

Thank you.