Add call hierarchy support for TypeScript 3.8

[rbuckton]

This adds Call Hierarchy support for TypeScript 3.8 and is the other half of microsoft/TypeScript#35176.

Related: #16110, microsoft/TypeScript#31863

cc: @mjbvz, @jrieken

[mjbvz]

Thanks for handling this!

The main change is that we can't bundle TS 3.8 with VS Code yet. Instead, let's just copy over the new TS types related to call hierarchy and keep using the TS 3.7 for everything else

[jrieken]

🕺 this is soo exciting

[rbuckton]

We only ship stable TS versions in stable VS Code. That means that we can't update this until TS 3.8 is released in mid February.

I'll update the PR shortly, that's actually how I had it set up before creating the PR.

[mjbvz]

Thanks! We'll ship VS Code 1.42 with support for call hierarchy support but users will still need to update to TS 3.8

Once we pick up TS 3.8 with VS code 1.43, it will be available to everyone. I'll also remove the copied over protocol types at that point