ECMA Script 6 introduce keyword constant. NetBeans should treat constants navigator and code completion in different way as variables.
Created attachment 159114 [details]
Constants have now "constant" icon in navigator and code completion item. In the editor the constant is treated as variable. So all features like mark occurrences, go to navigation, code completion, etc works as for a variable.
I have also added support of @constant tag in JsDoc.
Implemented in ecma6-truffel branch.