Merge branch 'mk/clarify-reset-tracking-db-in-ha' into 'master'

Geo: Clarify how to reset tracking DB in HA

See merge request gitlab-org/gitlab!28981

doc/administration/geo/replication/troubleshooting.md

@@ -486,9 +486,9 @@ to start again from scratch, there are a few steps that can help you:
 1. Reset the Tracking Database
 
    ```shell
-   gitlab-rake geo:db:drop
-   gitlab-ctl reconfigure
-   gitlab-rake geo:db:setup
+   gitlab-rake geo:db:drop  # on a secondary app node
+   gitlab-ctl reconfigure   # on the tracking database node
+   gitlab-rake geo:db:setup # on a secondary app node
    ```
 
 1. Restart previously stopped services