Bump phpdocumentor/guides-restructured-text from 1.7.0 to 1.7.3

Bumps [phpdocumentor/guides-restructured-text](https://github.com/phpDocumentor/guides-restructured-text) from 1.7.0 to 1.7.3.
- [Release notes](https://github.com/phpDocumentor/guides-restructured-text/releases)
- [Commits](phpDocumentor/guides-restructured-text@1.7.0...1.7.3)

---
updated-dependencies:
- dependency-name: phpdocumentor/guides-restructured-text
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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