Fix multiline completions when surroundings don't match completion text (#28995)

Follow up to the scenarios I overlooked in
https://github.com/zed-industries/zed/pull/28586.

Release Notes:

- N/A
1aa1b2bedeJoão Marcos committed on 4/17/2025, 6:37:38 PM· committed by GitHubparent58d8b91
2 files changedLine totals unavailable