Updated Firestore and GCS docs (#93)

Author: hiranya911

src/main/java/com/google/firebase/cloud/FirestoreClient.java

@@ -12,9 +12,9 @@
 import com.google.firebase.internal.NonNull;
 
 /**
- * FirestoreClient provides access to Google Cloud Firestore. Use this API to obtain a
- * <code>com.google.cloud.firestore.Firestore</code> instance, which provides methods for
- * updating and querying data in Firestore.
+ * {@code FirestoreClient} provides access to Google Cloud Firestore. Use this API to obtain a
+ * <a href="https://googlecloudplatform.github.io/google-cloud-java/latest/apidocs/com/google/cloud/firestore/Firestore.html">{@code Firestore}</a>
+ * instance, which provides methods for updating and querying data in Firestore.
  *
  * <p>A Google Cloud project ID is required to access Firestore. FirestoreClient determines the
  * project ID from the {@link com.google.firebase.FirebaseOptions} used to initialize the underlying
@@ -44,7 +44,8 @@ private FirestoreClient(FirebaseApp app) {
   /**
    * Returns the Firestore instance associated with the default Firebase app.
    *
-   * @return A non-null <code>com.google.cloud.firestore.Firestore</code> instance.
+   * @return A non-null <a href="https://googlecloudplatform.github.io/google-cloud-java/latest/apidocs/com/google/cloud/firestore/Firestore.html">{@code Firestore}</a>
+   *     instance.
    */
   @NonNull
   public static Firestore getFirestore() {
@@ -55,7 +56,8 @@ public static Firestore getFirestore() {
    * Returns the Firestore instance associated with the specified Firebase app.
    *
    * @param app A non-null {@link FirebaseApp}.
-   * @return A non-null <code>com.google.cloud.firestore.Firestore</code> instance.
+   * @return A non-null <a href="https://googlecloudplatform.github.io/google-cloud-java/latest/apidocs/com/google/cloud/firestore/Firestore.html">{@code Firestore}</a>
+   *     instance.
    */
   @NonNull
   public static Firestore getFirestore(FirebaseApp app) {

src/main/java/com/google/firebase/cloud/StorageClient.java

@@ -67,7 +67,8 @@ public static synchronized StorageClient getInstance(FirebaseApp app) {
    * configured via {@link com.google.firebase.FirebaseOptions} when initializing the app. If
    * no bucket was configured via options, this method throws an exception.
    *
-   * @return a cloud storage Bucket instance, or null if the configured bucket does not exist.
+   * @return a cloud storage <a href="https://googlecloudplatform.github.io/google-cloud-java/latest/apidocs/com/google/cloud/storage/Bucket.html">{@code Bucket}</a>
+   *     instance.
    * @throws IllegalArgumentException If no bucket is configured via <code>FirebaseOptions</code>,
    *     or if the bucket does not exist.
    */
@@ -79,7 +80,8 @@ public Bucket bucket() {
    * Returns a cloud storage Bucket instance for the specified bucket name.
    *
    * @param name a non-null, non-empty bucket name.
-   * @return a cloud storage Bucket instance, or null if the specified bucket does not exist.
+   * @return a cloud storage <a href="https://googlecloudplatform.github.io/google-cloud-java/latest/apidocs/com/google/cloud/storage/Bucket.html">{@code Bucket}</a>
+   *     instance.
    * @throws IllegalArgumentException If the bucket name is null, empty, or if the specified
    *     bucket does not exist.
    */