Add the man page description line as explicit markup at the top of each
Help/manual/*.rst file and scan it from conf.py to automatically
generate the man_pages Sphinx configuration value. This reduces the
number of places that need to be changed when a new manual is added.
Enable the --use-stderr behavior by default and ignore the old option.
Passing through the pipes allows color terminal output and other things
to work as if one ran the native build command directly.
Make the standard --help-* options available from all command-line
tools. Drop options that are no longer supported:
--copyright, --help-full, --help-html, --help-man,
--help-compatcommands, --help-custom-modules
De-duplicate Help/manual/*.1.rst help options by using an
OPTIONS_HELP.txt file included from each manual.
Add "Synopsis", "Description", and "See Also" manual page section
headers. These are typical of .1 man section pages. Also de-duplicate
the See Also section links using a separate LINKS.txt file included from
each manual.