Improve header-matching and file extension support
Improve header-matching and file extension support

* SunOS manpage files are split across 100 different extensions, most of
  them topic-specific (man3openssl, man3sysevent, etc). Thankfully, many
  include preprocessor hints as their first line ('\" te); the remainder
  simply alias other entries using ".so man3xyz/entry.man3xyz".

* While rare, the ".rof" extension has been encountered in the wild: see
  https://staff.fnwi.uva.nl/b.diertens/useful/gpresent/#download

Alhadis/language-roff,Alhadis/language-roff