Add recover options to gravity documentation (#631)

* Add recover options to gravity documentation

* Fix accidentally added bash

Signed-off-by: Christian König <ckoenig@posteo.de>

docs/database/gravity/recovery.md

@@ -0,0 +1,36 @@
+If the `gravity.db` database has been damaged, Pi-hole offers two build-in attemps to repair the database.
+
+## Recover
+
+Try to recover a damaged gravity database file.
+Pi-hole tries to restore as much as possible from a corrupted gravity database.
+Run:
+
+```bash
+pihole -g -r recover
+```
+
+## Recreate
+
+Create a new gravity database file from scratch. This will remove your existing gravity database and create a new file from scratch. If you still have the migration backup created when migrating to Pi-hole v5.0, Pi-hole will import these files.
+Run:
+
+```bash
+pihole -g -r recreate
+```
+
+---
+
+## Force recover (not recommended)
+
+!!! warning
+    This option is meant to be a last resort. Recovery is a fragile task consuming a lot of resources and shouldn't be performed unnecessarily.
+
+Force Pi-hole to run the recovery process even when no damage is detected.
+Run:
+
+```bash
+pihole -g -r recover force
+```
+
+ {!abbreviations.md!}

mkdocs.yml

@@ -99,6 +99,7 @@ nav:
       - 'Overview': database/gravity/index.md
       - 'Group management': database/gravity/groups.md
       - 'Examples': database/gravity/example.md
+      - 'Database recovery': database/gravity/recovery.md
   - 'FTLDNS':
     - 'Overview': ftldns/index.md
     - 'Configuration': ftldns/configfile.md