lint(spanner): Fixes comments.

Author: pratickchokhani

google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java

@@ -404,6 +404,10 @@ ByteString getTransactionId() {
       }
     }
 
+    /**
+     * Initializes the transaction with the timestamp specified within MultiUseReadOnlyTransaction.
+     * This is used only for fallback of PartitionQueryRequest and PartitionReadRequest with Multiplexed Session.
+     */
     void initFallbackTransaction() {
       synchronized (txnLock) {
         span.addAnnotation("Creating Transaction");

google-cloud-spanner/src/test/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClientMockServerTest.java

@@ -1573,8 +1573,9 @@ public void testPartitionedQuery_receivesUnimplemented_fallsBackToRegularSession
   }
 
   /**
-   * Tests the behavior of the server-side kill switch for partitioned query multiplexed sessions. 2
-   * PartitionQueryRequest should be received. First with Multiplexed session and second with
+   * Tests the behavior of the server-side kill switch for partitioned query multiplexed sessions.
+   * The BatchReadOnlyTransaction is initiated using BatchTransactionId.
+   * 2 PartitionQueryRequest should be received. First with Multiplexed session and second with
    * regular session.
    */
   @Test