Auto merge of #13792 - heycam:cleanup, r=emilio

Make some lists in regen.py neater.

<!-- Please describe your changes on the following line: -->

Having these lists of files and types with multiple entries per line makes it difficult to keep them sorted, especially when rebasing on other changes that touch the lists.  Having one per line makes that easier, and is also easier to read IMO. (I didn't touch `opaque_types` since I didn't know what to do with the comments, and it's a smaller list that isn't touched as often anyway.) r? @emilio

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13792)
<!-- Reviewable:end -->

0 files changed, 0 insertions, 0 deletions