Add group query operator to match groups by description

Change-Id: Icea8bfe031b93591bb2e76e99846c9c40846cc27
Signed-off-by: Edwin Kempin <ekempin@google.com>
diff --git a/Documentation/user-search-groups.txt b/Documentation/user-search-groups.txt
index cc753f6..4ecd143 100644
--- a/Documentation/user-search-groups.txt
+++ b/Documentation/user-search-groups.txt
@@ -10,6 +10,12 @@
 are added to the same query string, they further restrict the
 returned results.
 
+[[description]]
+description:'DESCRIPTION'::
++
+Matches groups that have a description that contains 'DESCRIPTION'
+(case-insensitive).
+
 [[inname]]
 inname:'NAMEPART'::
 +