Allow "Declare property" quick fix for enums

[mjbvz]

From @gbbarroso on June 21, 2018 1:29

The same way there's a "declare property" suggestion for classes when you use quick fix, there should be one for enums as well. Often you just want to create a new constant for an existing enum and you don't even care about the order / value, having this quick fix would save a trip back to the file containing the enum declaration.

To be clear, that's what I'm talking about:

Copied from original issue: microsoft/vscode#52528

[mhegazy]

PRs welcomed. should be a simple change.

[mhegazy]

//cc: @Kingwl

[Kingwl]

should i add that into add missing member fix?

In my opinion it loks like it would be easier as a separate fix. But could go either way.