Provide more context on derived obligation error primary label

Expand the primary span of E0277 when the immediate unmet bound is not what the user wrote:

```
error[E0277]: the trait bound `i32: Bar` is not satisfied
 --> f100.rs:6:6
  |
6 |     <i32 as Foo>::foo();
  |      ^^^ the trait `Bar` is not implemented for `i32`, which is required by `i32: Foo`
  |
help: this trait has no implementations, consider adding one
 --> f100.rs:2:1
  |
2 | trait Bar {}
  | ^^^^^^^^^
note: required for `i32` to implement `Foo`
 --> f100.rs:3:14
  |
3 | impl<T: Bar> Foo for T {}
  |         ---  ^^^     ^
  |         |
  |         unsatisfied trait bound introduced here
```

Fix #40120.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/ui/suggestions/issue-96223.stderr b/tests/ui/suggestions/issue-96223.stderr
index a54a4e7b3be..4a77b240f3e 100644
--- a/tests/ui/suggestions/issue-96223.stderr
+++ b/tests/ui/suggestions/issue-96223.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `for<'de> EmptyBis<'de>: Foo<'_>` is not satisfied
   --> $DIR/issue-96223.rs:49:17
    |
 LL |     icey_bounds(&p);
-   |     ----------- ^^ the trait `for<'de> Foo<'_>` is not implemented for `EmptyBis<'de>`
+   |     ----------- ^^ the trait `for<'de> Foo<'_>` is not implemented for `EmptyBis<'de>`, which is required by `Empty: Dummy<EmptyMarker>`
    |     |
    |     required by a bound introduced by this call
    |