CodeMirror: Add missing SASS mode to ModeInfo

This was added in CodeMirror 3.01, but has been left out for a while.

Change-Id: Ib7a15f40760f47bdabfcf588479bcf6736a97a34

gerrit-gwtui/src/main/java/net/codemirror/mode/ModeInfo.java

@@ -119,6 +119,7 @@ public class ModeInfo extends JavaScriptObject {
       Modes.I.ruby(),
       Modes.I.rust(),
       Modes.I.sas(),
+      Modes.I.sass(),
       Modes.I.scheme(),
       Modes.I.shell(),
       Modes.I.smalltalk(),