Rollup merge of #129170 - artemagvanian:span-to-location, r=celinval

Add an ability to convert between `Span` and `visit::Location`

AFAIK, there is no way to create a `Location` from a `Span` because its only field is private. This makes it impossible to use visitor methods like `visit_statement` or `visit_terminator`.

This PR adds an implementation for`From<Span>` for `Location` to fix this.

r? ```@celinval```

Author: workingjubilee