add highlight rules for operators

src/ace/mode/JavaScriptHighlightRules.js

@@ -88,6 +88,9 @@ JavaScriptHighlightRules = function() {
                 }
             },
             regex : "[a-zA-Z_][a-zA-Z0-9_]*\\b"
+        }, {
+            token : "operator",
+            regex : "!|\\$|%|&|\\*|\\-\\-|\\-|\\+\\+|\\+|~|===|==|=|!=|!==|<=|>=|<<=|>>=|>>>=|<>|<|>|!|&&|\\|\\||\\?\\:|\\*=|%=|\\+=|\\-=|&=|\\^=|\\b(in|instanceof|new|delete|typeof|void)"
         }, {
             token : "lparen",
             regex : "[\\[\\(\\{]"

src/ace/theme/tm.css

@@ -58,6 +58,10 @@
   color: rgb(60, 76, 114);
 }
 
+.ace-tm .ace_line .ace_operator {
+  color: rgb(104, 118, 135);
+}
+
 .ace-tm .ace_line .ace_string {
   color: rgb(3, 106, 7);
 }