Remove the code responsible for implicitly compressing manpages as .gz
files. It has been established that manpage compression is a distro
packager's task, with existing distros already having their own
implementations of compression.
Fixes#4330
This is a cosmetic change because github seems to interpret those
correctly. Nonetheless, it adds unnecessary noise and makes people
modifying the pages think it might be needed.
See syntax guide at https://guides.github.com/features/mastering-markdown/
This allows us to more easily have the documentation in sync with
the source code as people will have to document new features etc
right at the time where they implement it.
Jussi Pakkanen