Auto merge of rust-lang#146121 - Muscraft:filter-suggestion-parts, r=petrochenkov

fix: Filter suggestion parts that match existing code

While testing my changes to make `rustc` use `annotate-snippets`, I encountered a new `clippy` test failure stemming from [two](https://github.com/rust-lang/rust/pull/145273/files#diff-6e8403e31463539666afbc00479cb416dc767a518f562b6e2960630953ee7da2R275-R278) [suggestion](https://github.com/rust-lang/rust/pull/145273/files#diff-6e8403e31463539666afbc00479cb416dc767a518f562b6e2960630953ee7da2R289-R292) output changes in rust-lang#145273. The new output in these two cases feels like a regression as it is not as clear as the old output, and adds unnecessary information.

Before rust-lang#145273 (`Diff` style)
![before](https://github.com/user-attachments/assets/36f33635-cbce-45f1-823d-0cbe6f0cfe46)

After rust-lang#145273 ("multi-line" style)
![after](https://github.com/user-attachments/assets/d4cb00b8-5a42-436e-9329-db84347138f0)

The reason for the change was that a new suggestion part (which matches existing code) was added on a different line than the existing parts, causing the suggestion style to change from `Diff` to "multi-line". Since this new part matches existing code, no code changes show up in the output for it, but it still makes the suggestion style "multi-line" when it doesn't need to be.

To get the old output back, I made it so that suggestion parts that perfectly match existing code get filtered out.

try-job: aarch64-apple

Author: bors

tests/ui/bool_assert_comparison.stderr

@@ -272,10 +272,8 @@ LL |     assert_eq!(a!(), true);
    |
 help: replace it with `assert!(..)`
    |
-LL |         true
-...
-LL |
-LL ~     assert!(a!());
+LL -     assert_eq!(a!(), true);
+LL +     assert!(a!());
    |
 
 error: used `assert_eq!` with a literal bool
@@ -286,10 +284,8 @@ LL |     assert_eq!(true, b!());
    |
 help: replace it with `assert!(..)`
    |
-LL |         true
-...
-LL |
-LL ~     assert!(b!());
+LL -     assert_eq!(true, b!());
+LL +     assert!(b!());
    |
 
 error: used `debug_assert_eq!` with a literal bool