If there are multiple prefixed/non-prefixed @keyframes with the same name;
* non-prefixed rule overrides earlier rules.
* prefixed rule overrides earlier prefixed rules.
replace match by if let statements if possible
<!-- Please describe your changes on the following line: -->
Hi there,
This PR replaces `match` statements by `if let` when possible.
Thanks for reviewing
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#14788
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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because this PR is a code cleanup patch.
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