Distinguishing suggestions from global scope from local suggestions

From https://github.com/Microsoft/vscode/issues/59437

Search Terms:

• TSServer
• completions
• suggestions

Code
For the example ts file:

class FooClass {
    toString(): void {
        |
    }
}

Trigger suggestions at the | inside the toString method

Problem
We get back two completions from completionInfo:

     {
            "name": "toString",
            "kind": "function",
            "kindModifiers": "declare",
            "sortText": "0"
        },
        {
            "name": "toString",
            "kind": "method",
            "kindModifiers": "",
            "sortText": "0",
            "insertText": "this.toString"
        },

However when we then make the completionEntryDetails request, we can only pass the identifier name: "toString". This makes it unclear which completion entry we are actually requesting completion details for.

Proposal
completionEntryDetails already has a source field that is used to identify when a suggestion is an auto import. I believe that this field could also be used for global symbols, such as when a symbol name comes from a global lib.d.ts file. In this case, the first toString suggestion comes from a global in dom.d.ts

Use the FooClass example to reproduce the duplicate toString completions returned by completionInfo. Read how completionEntryDetails currently uses source for auto imports, then evaluate the proposed global-symbol case from dom.d.ts; done means callers can distinguish the entries and request the matching details.