Previously, when I was invoking `tg patch` the following used to happen:
1. .topmsg content was sent directly to _terminal_
2. for each file in the patch, its diff was generated with `git diff`
and sent to *PAGER*
3. trailing 'tg: ...' was sent to terminal again
So the problem is that while `tg patch >file` works as expected, plain
`tg patch` does not -- in pager there is only a part of the whole patch
(first file diff) and header and trailer are ommitted.
I've finally decided to fix this inconvenience, and the way it works is
like in git -- we just hook `setup_pager` function in commands which
need to be paginated.
Signed-off-by: Kirill Smelkov <kirr@landau.phys.spbu.ru>