Clean up mandoc lint
Running git-pbchk runs mandoc lint which can generate a number
of errors. It would be nice to fix these once and for all.
Across all our man pages at the present time, we have the following number of problems (across 3706 different man pages):
2 WARNING: skipping paragraph macro: br after SH
3 WARNING: skipping paragraph macro: br after SS
109 WARNING: whitespace at end of input line
842 UNSUPP: unsupported control character: 0x7
2168 WARNING: skipping paragraph macro: sp after SS
19352 WARNING: skipping paragraph macro: sp after SH
It would be fairly straightforward to automatically fix those.
This ignores the following types of warnings:
invalid escape sequence
cannot parse date, using it verbatim
lower case character in document title
Which either need manual intervention or which would change the
output, so are deferred to a separate issue.