Provide direct link to REST API documentation

The REST API is a first-class feature that we want to
encourage people to use. Providing a high-level link
helps increase visibility.

Change-Id: I5af19d7d9fee1ae2ba67352f2c06cedfb4f8a9f6

gerrit-gwtui/src/main/java/com/google/gerrit/client/Gerrit.java

@@ -680,6 +680,7 @@ public class Gerrit implements EntryPoint {
       addDocLink(m, C.menuDocumentationSearch(), "user-search.html");
       addDocLink(m, C.menuDocumentationUpload(), "user-upload.html");
       addDocLink(m, C.menuDocumentationAccess(), "access-control.html");
+      addDocLink(m, C.menuDocumentationAPI(), "rest-api.html");
       menuLeft.add(m, C.menuDocumentation());
     }
 

gerrit-gwtui/src/main/java/com/google/gerrit/client/GerritConstants.java

@@ -88,6 +88,7 @@ public interface GerritConstants extends Constants {
   String menuDocumentationSearch();
   String menuDocumentationUpload();
   String menuDocumentationAccess();
+  String menuDocumentationAPI();
 
   String searchHint();
   String searchButton();

gerrit-gwtui/src/main/java/com/google/gerrit/client/GerritConstants.properties

@@ -71,6 +71,7 @@ menuDocumentationIndex = Index
 menuDocumentationSearch = Searching
 menuDocumentationUpload = Uploading
 menuDocumentationAccess = Access Controls
+menuDocumentationAPI = REST API
 
 searchHint = Change #, SHA-1, tr:id or owner:email
 searchButton = Search