Add XQuery keywords.

lib/ace/mode/xquery_highlight_rules.js

@@ -28,8 +28,8 @@ var XQueryHighlightRules = function() {
   var keywords = lang.arrayToMap(
     ("return|for|let|where|order|by|declare|function|variable|xquery|version|option|namespace|import|module|when|encoding|" +
      "switch|default|try|catch|group|tumbling|sliding|window|start|end|at|only|" +
-     "using|stemming|" +
-     "while|" + 
+     "using|stemming|collection|schema|" +
+     "while|validate|on|nodes|index|" + 
      "external|" +
      "if|then|else|as|and|or|typeswitch|case|ascending|descending|empty|in|count|updating|insert|delete|replace|value|node|attribute|text|element|into|of|with|contains").split("|")
     );