* rename socket file, make example more precise, use long parameter name
* correct path
* use the correct path to the configuration file according to the documentation
* rename the socket unit back to 'gitea.main.socket', explicitly indicate that the socket unit should use the service file 'gitea.service'
* Update the provided gitea.service since we have graceful restarting again
* Update contrib/systemd/gitea.service
Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>
When using unix socket as listener (`HTTP_ADDR = /run/gitea/gitea.socket`) then it's required to have the folder `/run/gitea` with appropriate owner/group. Manual creation leads to vanishing after reboot. This directive enables Systemd to handle this.
