Add index.md at "geo tracking database" link in troubleshooting.md

doc/administration/geo/replication/troubleshooting.md

@@ -1146,7 +1146,7 @@ Geo::TrackingBase::SecondaryNotConfigured: Geo secondary database is not configu
 
 On a Geo primary site this error can be ignored.
 
-This happens because GitLab is attempting to display registries from the [Geo tracking database](../../../administration/geo/#geo-tracking-database) which doesn't exist on the primary site (only the original projects exist on the primary; no replicated projects are present, therefore no tracking database exists).
+This happens because GitLab is attempting to display registries from the [Geo tracking database](../../../administration/geo/index.md#geo-tracking-database) which doesn't exist on the primary site (only the original projects exist on the primary; no replicated projects are present, therefore no tracking database exists).
 
 ## Fixing client errors