docs: update url to manifest.json.

README.md

@@ -75,12 +75,17 @@ Enable this playlist, currently ignored.
 
 Add the [plugin repository](https://jellyfin.org/docs/general/server/plugins/#catalog)
 to Jellyfin:
-`https://gitea.redxef.at/redxef/jellyfin-smart-playlist/raw/branch/manifest/manifest.json`
+`https://git.redxef.at/redxef/jellyfin-smart-playlist/raw/branch/manifest/manifest.json`
 
 Go to `Dashboard>Catalog>(Gear)>(Plus)` and paste the provided link into
 the field labeled `Repository URL`, give the plugin a descriptive name
 too.
 
+## Mirror
+
+There is a mirror at
+[codeberg.org/redxef/jellyfin-smart-playlist](https://codeberg.org/redxef/jellyfin-smart-playlist).
+
 ## Releasing a new version
 
 1. Write the changelog: `git log --oneline $prev_version..`