Auto merge of #23532 - est31:unused_code_removal_4, r=emilio

Remove unused code (4/4)

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Fourth and final PR in a series of PRs to remove unused/dead code from servo, powered by an (upcoming) tool of mine. Please take a look and tell me if you want to keep something.

* First PR: #23477
* Second PR: #23498
* Third PR: #23499

Shortstat of the combined PR series:
```
47 files changed, 7 insertions(+), 805 deletions(-)
```

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because they only remove dead code

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components/style/invalidation/element/restyle_hints.rs

@@ -105,12 +105,6 @@ impl RestyleHint {
         Self::empty()
     }
 
-    /// Creates a new `RestyleHint` that indicates the element must be
-    /// recascaded.
-    pub fn recascade_self() -> Self {
-        RestyleHint::RECASCADE_SELF
-    }
-
     /// Returns a hint that contains all the replacement hints.
     pub fn replacements() -> Self {
         RestyleHint::RESTYLE_STYLE_ATTRIBUTE | Self::for_animations()