Add missing title for bookmark-scene

Localization/app.json

@@ -694,6 +694,9 @@
             "new_in_mastodon": "New in Mastodon",
             "multiple_account_switch_intro_description": "Switch between multiple accounts by holding the profile button.",
             "accessibility_hint": "Double tap to dismiss this wizard"
+        },
+        "bookmark": {
+            "title": "Bookmarks"
         }
     }
 }