LSP references cover into and from

[dev-ardi]

Right now they don't really do much:

struct A;
struct B;
impl From<A> for B {
    fn from(_: A) -> B {
        B
    }
}

fn foo() -> B {
    A.into()
}

I would expect LSP references to show up in:

• A: Show the .into() call. It works for B
• from: show the .into() call, also show up in "LSP incoming calls"

I would also expect this to work on ? after it's been desugared.

[roife]

We might need to implement #18316 first.

[Veykril]

That does not sound like something the references call should do to me, as raised #18316 would cover this more correctly.