PolyGerrit: Add ':' to autocompleted predicates in search bar

A lot more helpful since predicates must always be prefixed with the
':' separator.

Change-Id: Ie5e4f2ee865c555f1d4356766f26868788f2296c

polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.js

@@ -16,31 +16,31 @@
 
   // Possible static search options for auto complete.
   var SEARCH_OPERATORS = [
-    'added',
-    'age',
+    'added:',
+    'age:',
     'age:1week', // Give an example age
-    'author',
-    'branch',
-    'bug',
-    'cc',
+    'author:',
+    'branch:',
+    'bug:',
+    'cc:',
     'cc:self',
-    'change',
-    'comment',
-    'commentby',
-    'commit',
-    'committer',
-    'conflicts',
-    'deleted',
-    'delta',
-    'file',
-    'from',
-    'has',
+    'change:',
+    'comment:',
+    'commentby:',
+    'commit:',
+    'committer:',
+    'conflicts:',
+    'deleted:',
+    'delta:',
+    'file:',
+    'from:',
+    'has:',
     'has:draft',
     'has:edit',
     'has:star',
     'has:stars',
-    'intopic',
-    'is',
+    'intopic:',
+    'is:',
     'is:abandoned',
     'is:closed',
     'is:draft',
@@ -53,22 +53,22 @@
     'is:reviewer',
     'is:starred',
     'is:watched',
-    'label',
-    'message',
-    'owner',
-    'ownerin',
-    'parentproject',
-    'project',
-    'projects',
-    'query',
-    'ref',
-    'reviewedby',
-    'reviewer',
+    'label:',
+    'message:',
+    'owner:',
+    'ownerin:',
+    'parentproject:',
+    'project:',
+    'projects:',
+    'query:',
+    'ref:',
+    'reviewedby:',
+    'reviewer:',
     'reviewer:self',
-    'reviewerin',
-    'size',
-    'star',
-    'status',
+    'reviewerin:',
+    'size:',
+    'star:',
+    'status:',
     'status:abandoned',
     'status:closed',
     'status:draft',
@@ -76,8 +76,8 @@
     'status:open',
     'status:pending',
     'status:reviewed',
-    'topic',
-    'tr',
+    'topic:',
+    'tr:',
   ];
 
   var SELF_EXPRESSION = 'self';