…oblem)

1. `#[implicit_caller_location]` -> `#[blame_caller]`. The internal
    attribute remains as `#[rustc_implicit_caller_location]`.
2. Imported discussion about "my fault" vs "your fault". Ensure only
    `panic!()` and `assert!()` will get caller's location.
3. Added DbC as a viable alternative (in terms of syntax).
4. Removed the section about `Try` since we decided not to support
    `#[blame_caller]` on traits.