In the fallback code to look for manual pages without using mandoc.db(5),
accept files "man<one-digit-section>/<name>.<full-section>"
in addition to the already supported "man<full-section>/name.[01-9]*".
Needed for example on Alpine Linux which puts its Perl manuals
into "man3/<name>.3pm" and the POSIX manuals into "man3/<name>.3p".
While here, allow the glob(3) at the end of fs_lookup() to add multiple
matches to the result set. This improves man -w output and may also
help some cases of plain man(1), allowing main() to prioritize properly
rather than fs_lookup() picking a random match.
Issue reported and patch tested
by Soeren Tempel <soeren at soeren hyphen tempel dot net>.