Add field enum to aid in querying

Is it possible to add an enum to the type template with all the field names? This helps when you have to refer to a field by name and aren't using the getter/setter accessors. I think this would be useful when building queries to know that you don't have any typos.

Is there another way of doing this that I'm missing?

Here's a simple implementation but I don't know ST4 enough to know the right way of omitting the comma on the last enum item:
https://github.com/forcedotcom/wsc/commit/5a87dd926d6d82dfdd81f11a139fae40d0561217

Happy to open a PR from my fork if this would be helpful