So they are consistent with the way we’re building man pages in other
projects, and because some people are allergic to XML.
This changes the build-time dependencies from `xsltproc` to `rst2man`,
and also takes the opportunity to change the `-Dman` Meson option from a
boolean to a feature (so you should use `-Dman-pages={enabled,disabled}`
now, rather than `-Dman={true,false}`).
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
