Update comment

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java

@@ -558,8 +558,10 @@ public void releaseQuery(Query query) {
             queryCache.updateQueryData(queryData);
           }
 
-          // We remove both locally edited documents and documents that are associated via the query
-          // cache.
+          // Documents send via Watch are automatically dereferenced when we remove a query's
+          // target data from the reference delegate. Since this does not remove references for
+          // locally mutated documents, we have to remove the target associations for these
+          // documents manually.
           ImmutableSortedSet<DocumentKey> removedReferences =
               localViewReferences.removeReferencesForId(queryData.getTargetId());
           for (DocumentKey key : removedReferences) {