Add missing @Override annotations

Change-Id: I261ca6c6348a4ecde00a0db6188df5b58fcaf788

src/main/java/com/googlesource/gerrit/plugins/xdocs/client/XDocApi.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/client/XDocApi.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/client/XDocApi.java
index 7fa7b01..65d39fe 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/xdocs/client/XDocApi.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/client/XDocApi.java
@@ -46,6 +46,7 @@
     RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, url);
     try {
       builder.sendRequest(null, new RequestCallback() {
+        @Override
         public void onResponseReceived(Request request, Response response) {
           int status = response.getStatusCode();
           if (200 <= status && status < 300) {
@@ -56,6 +57,7 @@
           }
         }
 
+        @Override
         public void onError(Request request, Throwable caught) {
           callback.onFailure(caught);
         }

src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java
index c55944a..55b7964 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java
@@ -129,6 +129,7 @@
     return this;
   }
 
+  @Override
   public String toString() {
     return html.toString();
   }