* docs: update heading
This section covers more paths than the 3 listed in the heading.
* setting: change PIDFile default from /var/run/gitea.pid to /run/gitea.pid
On most modern distributions, /var/run is deprecated and only kept for
backwards compat according to
https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05s13.html, and is a
symlink to `/run/` on modern distributions.
Old Distros that still don't have `/run` can update the gitea default as
described in from-source.en-us.md to point to the old location.
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>