Add support for LSP `callHierarchy`

Hi, thanks for amazing work in ALE, and especially the ty integration.

Coincidentally, [ty recently added support for `callHierarchy`](https://github.com/astral-sh/ty/issues/1976) -- which is the LSP functionality that allows you to find all incoming calls to a function, directly or indirectly via other functions.

I searched the issue tracker and it appears this hasn't been discussed before, so I'm creating an issue for it.

Usually IDEs show a tree-like view of all the call sites, but I'm sure just a quickfix list is already useful enough of an integration.