Auto merge of #119807 - Emilgardis:track_caller_from_impl_into, r=Nilstrieb

Add `#[track_caller]` to the "From implies Into" impl

This pr implements what was mentioned in https://github.com/rust-lang/rust/issues/77474#issuecomment-1074480790

This follows from my URLO https://users.rust-lang.org/t/104497

```rust
#![allow(warnings)]
fn main() {
    // Gives a good location
    let _: Result<(), Loc> = dbg!(Err::<(), _>(()).map_err(|e| e.into()));

    // still doesn't work, gives location of `FnOnce::call_once()`
    let _: Result<(), Loc> = dbg!(Err::<(), _>(()).map_err(Into::into));
}

#[derive(Debug)]
pub struct Loc {
    pub l: &'static std::panic::Location<'static>,
}

impl From<()> for Loc {
    #[track_caller]
    fn from(_: ()) -> Self {
        Loc {
            l: std::panic::Location::caller(),
        }
    }
}
```

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