Address review feedback

Author: jmwski

.changeset/hip-turtles-travel.md

@@ -2,4 +2,4 @@
 '@firebase/database': patch
 ---
 
-RTDB query gets shouldn't send server requests for listened-to data
+get()s issued for queries that are being listened to no longer send backend requests.

packages/database/src/core/Repo.ts

@@ -319,6 +319,7 @@ export class Repo {
    * @param query - The query to surface a value for.
    */
   getValue(query: Query): Promise<DataSnapshot> {
+    // Only active queries are cached. There is no persisted cache.
     const cached = this.serverSyncTree_.calcCompleteEventCache(query.path);
     if (!cached.isEmpty()) {
       return Promise.resolve(