Many pages: Use man3type/ and man2type/ for type pages

Many pages: Use man3type/ and man2type/ for type pages

Quoting Ingo:

[
The mandoc(1) program is also able to handle paths like
"man3/id_t.3type".  It will consider that page to be *both* in section
"3" (as specified by the directory name) and in section "3type" (as
specified by the file name and by the .TH macro).  I would consider
it better style to keep section names consistent, i.e. to use either
"man3/id_t.3" .TH id_t 3 or "man3type/id_t.3type" .TH id_t 3type,
but it's not a big deal: since many systems (in particular various
Linux distros) suffer from such inconsistencies, handling such
inconsistencies gracefully is an important feature that certainly
won't get removed.
]

Let's be nice, and do things right here, in the hope that others
may follow the example.

===

Most of this patch has been scripted:

$ mkdir man2type man3type
$ find man2 | grep type$ | while read f; do mv -t man2type $f; done
$ find man3 | grep type$ | while read f; do mv -t man3type $f; done
$ grep -rl man3/.*type man* | xargs sed -i 's,man3/,man3type/,'

Apart from that, I adapted the Makefiles, and moved va_list into
the man3type subsection (it was accidentally placed in the main 3
section).

Link: <https://lore.kernel.org/linux-man/YrB66rgFZqryrmpt@asta-kit.de/T/#u>
Reported-by: Ingo Schwarze <schwarze@usta.de>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>