starting work

Notes to self:

• Related: Fix auto-complete snippet cursor placement pxt#7291
• at this line, we're getting "anyButton" instead of "A": https://github.com/microsoft/pxt/blob/master/pxtcompiler/emitter/snippets.ts#L211
• dazuniga/a_button_snippet

Note that this repros on the released version of Arcade today. This dates back to before at least Aug 11th.

The issue is pretty subtle. We have an assumption in our language service that each Symbol will have one Snippet.
However this isn't true. Both of these use the same symbol (onEvent) and yet their snippets must be different:

controller.anyButton.onEvent
controller.A.onEvent

In both of these completion cases, we were returning the snippet as: controller.anyButton.onEvent(Pressed, ...)

I'll need to think about the solution.

One possible solution: return the snippet in parts. So instead of one string: controller.anyButton.onEvent(Pressed, ...) we return a series of qualifiers ["controller", "anyButton"] and the function string onEvent(Pressed, ...) then the insert location can choose which qualifiers to include or not. In the case that we're already several "."s in, we discard all the qualifiers.

Doesn't feel particularly principled but might be the smallest fix.

We switched to the stock monaco service