gr-search-bar: Autosuggest before/after

Change-Id: I4e01ff5e3acbfd8fa53c764f8b68b029195c91fd
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
index 4143d33..3f53847 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
@@ -41,10 +41,12 @@
 // Possible static search options for auto complete, without negations.
 const SEARCH_OPERATORS: ReadonlyArray<string> = [
   'added:',
+  'after:',
   'age:',
   'age:1week', // Give an example age
   'assignee:',
   'author:',
+  'before:',
   'branch:',
   'bug:',
   'cc:',
@@ -90,6 +92,8 @@
   'is:watched',
   'is:wip',
   'label:',
+  'mergedafter:',
+  'mergedbefore:',
   'message:',
   'onlyexts:',
   'onlyextensions:',