Allow interception of Completion list and its transformation

[vscodenpa]

Ability to modify a Completion list right before it is rendered seems like missed opportunity, that would allow Plugin dev to change way completions are displayed to the user, this can be done in IntelliJ IDEs rather easily, and would be great if it was possible for VS-Code

I searched the whether it is possible similarly to IntelliJ IDEs to intercept the list of completions, inspect them and then modify the final list the way you like before it gets rendered.

There could be two approaches

• same as IntelliJ - have CompletionItemProvider receive 'Completion list so far' and allow it to be inspected/manipulated right there
• have a dedicated CompletionInterceptor that gets the list before it is rendered, so transformation is possible before rendering