Support diagnostics references from TypeScript

[mjbvz]

Tracks the VS Code side support for microsoft/TypeScript#25257

This feature adds related information on some diagnostics

[JacksonKearl]

I was only able to get this to trigger on use before declaration, I think there should be more trigger, based on the related issue on the TS side. @mjbvz this was my file:

import * as express from 'express'

let a: unknown = {}

let ob = {
    'aaa': 1,
    'bbb': 2
}

let b: number = a // nothing for incompatible assignment

let c = express(); // nothing for calling CommonJS import (this was the big screenshot in the linked issue)

ob.aab = 4 // nothing for "did you mean"

r = 4; // does trigger:  "r is declared here: ..."
let r: number;

[mjbvz]

I confirmed that feature does the right thing on our side. Here are the followups from your example:

1. Opened No related error spans return for type assignment mismatch TypeScript#26145 for this
2. Not sure why this would is error since the @types typings do indicate that the exported namespace is a function. Will follow up to see if this is expected or not
3. Does show up if you make the name slightly longer: aaab. TS is a bit conservative with 'did you mean' checks. Will open another issue for this