editor: Fix highlight and selection overlap causing flicker while selecting (#40168)

Regressed in https://github.com/zed-industries/zed/pull/39857, only on
Nightly.

Release Notes:

- N/A
d4cc4f8ca7Smit Barmase committed on 10/14/2025, 10:35:21 AM· committed by GitHubparentc61429e
1 file changedLine totals unavailable