## Summary of the Pull Request
This replaces the `GridLines` enum in the renderers with a `til::enumset` type, avoiding the need for the various `WI_IsFlagSet` macros and flag operators.
## References
This is followup to PR #10492 which introduced the `enumset` class.
## PR Checklist
* [ ] Closes #xxx
* [x] CLA signed.
* [ ] Tests added/passed
* [ ] Documentation updated.
* [ ] Schema updated.
* [ ] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan.
## Validation Steps Performed
I've manually confirmed that all the different gridlines are still rendering correctly in both the GDI and DX renderers.