Remove automatic cleanup section because it does not work

- No systemd session is available for podman in crontab entries and there appears to be no proper way to get one without a PTY...

docs/hosting-runners.md

@@ -33,19 +33,10 @@ machinectl shell --uid forgejo-runner # <-- This is basically "sudo -Hi XXX" but
 ```
 
 ```bash
-systemctl --user enable --now podman.socket
+systemctl --user enable --now podman.socket podman
 echo 'export DOCKER_HOST=unix://$XDG_RUNTIME_DIR/podman/podman.sock' >> ~/.profile
 ```
 
-#### Automatic podman cleanup on reboot
-
-```bash
-crontab -e
-```
-```cronexp
-@reboot podman system cleanup --all --force
-```
-
 ### 4. Install the forgejo-runner
 
 ```bash