I'm just getting started with extension development so please forgive me if this is a inappropriate feature request. I'm looking to create an extension that with allow me to select a block of code in a source language (i.e. html) and have the option to edit the block in a different language (i.e. jade/pug). I would imagine it would behave similarly to the TextDocumentContentProvider, but have the ability to edit in the secondary window, then transpile back to the source when completed. I didn't see anything in the API documents that would allow me to do this now. Thanks.