[Groff] ISO/IEC 9899:2011

[Kristaps Dzonsons]

Hello,

The enclosed patch accepts `-isoC-2011' to print the now-official 
standard name, ISO/IEC 9899:2011, for mdoc.  If it looks alright, I'll 
update mandoc(1) similarly.

Note that this uses `-isoC-2011' instead of `-isoC-11'.  Maybe this is 
confusing, but I drew from how POSIX symbols increment from two to four 
digits when spanning 2000 (e.g. `-p1003.1-96' to `-p1003.1-2001'). 
Sound reasonable?

Thanks!

Kristaps

groff-c11.diff
Description: Text document