Change query language: Add 'pending' as alias for 'open'

Make is:pending an alias for is:open, in case users are familiar with
the concept of a "pending code review" and are trying to search.

Change-Id: I550a9a22004d5a62f9a17c77ae5ebdf54c973170

Documentation/user-search.txt

@@ -265,7 +265,7 @@ is:reviewer::
 True on any change where the current user is a reviewer.
 Same as `reviewer:self`.
 
-is:open::
+is:open, is:pending::
 +
 True if the change is either open or submitted, merge pending.
 
@@ -287,7 +287,7 @@ True if the change has no merge conflicts and could be merged into its
 destination branch.
 
 [[status]]
-status:open::
+status:open, status:pending::
 +
 True if the change state is either 'review in progress' or 'submitted,
 merge pending'.

gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

@@ -269,7 +269,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
 
   @Operator
   public Predicate<ChangeData> status(String statusName) {
-    if ("open".equals(statusName)) {
+    if ("open".equals(statusName) || "pending".equals(statusName)) {
       return status_open();
 
     } else if ("closed".equals(statusName)) {