Provide related information to diagnostics

[spahnke]

Adds related information to a diagnostic if the TypeScript service reports any. An example would be Did you forget to use 'await'? in the following code.

function foo(bar: number) {}

function bar() {
    const baz = Promise.resolve(1);
    foo(baz);
    //  ~~~ Related: Did you forget to use 'await'?
}

[orta]

Thanks! I'll get this merged into our nightly typescript builds

[orta]

Nice one, this works well - Anders asked about the implement interface fixit yesterday

[alexdima]

Thank you, works nicely ! ❤️