Bump rewriter from de9f96d to 9e81a52

Bumps [rewriter](https://github.com/mit-plv/rewriter) from `de9f96d` to `9e81a52`.
- [Release notes](https://github.com/mit-plv/rewriter/releases)
- [Commits](mit-plv/rewriter@de9f96d...9e81a52)

---
updated-dependencies:
- dependency-name: rewriter
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>