chore(deps): update rust crate diffy to v0.5.1 (#4466)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [diffy](https://redirect.github.com/bmwill/diffy) | dependencies |
patch | `0.5.0` → `0.5.1` |

---

> [!WARNING]
> Some dependencies could not be looked up. Check the [Dependency
Dashboard](../issues/1) for more information.

---

### Release Notes

<details>
<summary>bmwill/diffy (diffy)</summary>

###
[`v0.5.1`](https://redirect.github.com/bmwill/diffy/blob/HEAD/CHANGELOG.md#051---2026-07-18)

[Compare
Source](https://redirect.github.com/bmwill/diffy/compare/0.5.0...0.5.1)

##### Fixed

- [#&#8203;85](https://redirect.github.com/bmwill/diffy/pull/85)
  Merge conflict markers are now always placed on their own lines.
  Previously, a conflicting hunk at the end of a file without a trailing
  newline glued the next marker onto its last content line, producing
  unparseable output. This matches `git merge-file --diff3` behavior.

</details>

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Cargo.lock

@@ -2448,9 +2448,9 @@ checksum = "ab03c107fafeb3ee9f5925686dbb7a73bc76e3932abb0d2b365cb64b169cf04c"
 
 [[package]]
 name = "diffy"
-version = "0.5.0"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05264ab2aab4fb952fc4b0f3f6eff1ddfb4563064053a4ea174d91537584a769"
+checksum = "10aec8f7f9393bd6a4f2762be0ceb012d3cbe2478987258cc9960de148561914"
 dependencies = [
  "hashbrown 0.17.1",
 ]