expose EditorService#{editorsWithModels,observeEditorAndModel}
Created by: sqs
Common use case for components are to listen for changes to:
- all editors and model languages, or
- a single editor and its model text
This commit adds these new APIs. In doing so, it also fixes #4072 ("Experimental text field completion" interaction with code host text inputs).
fix #4072
cc @slimsag @christinaforney who had expressed interest in getting this fixed