Make logging for drop-tracking easier to read.

Make logging for drop-tracking easier to read.

Some of these are a little questionable because the output is so much longer, but I would really love to keep the bit that adds the pretty-printed expression to the generated CFG .dot file.

Before:
```
DEBUG rustc_typeck::check::generator_interior::drop_ranges::record_consumed_borrow consume PlaceWithHirId { hir_id: HirId { owner: DefId(0:7 ~ default_struct_update[79f9]::foo), local_id: 15 }, place: Place { base_ty: impl std::future::Future<Output = ()>, base: Rvalue, projections: [] } }; diag_expr_id=HirId { owner: DefId(0:7 ~ default_struct_update[79f9]::foo), local_id: 15 }, using parent expr HirId { owner: DefId(0:7 ~ default_struct_update[79f9]::foo), local_id: 49 }
```

After:
```
DEBUG rustc_typeck::check::generator_interior::drop_ranges::record_consumed_borrow consume PlaceWithHirId { hir_id: HirId { owner: DefId(0:7 ~ default_struct_update[79f9]::foo), local_id: 15 }, place: Place { base_ty: impl std::future::Future<Output = ()>, base: Rvalue, projections: [] } }; diag_expr_id=expr from_config(Config {
        nickname: None,
        ..Default::default()
    }) (hir_id=HirId { owner: DefId(0:7 ~ default_struct_update[79f9]::foo), local_id: 15 }), using parent expr
    .await (hir_id=HirId { owner: DefId(0:7 ~ default_struct_update[79f9]::foo), local_id: 49 })
```