Fix handling of empty blocks in BlockMap::chunks (#25031)

Closes https://github.com/zed-industries/zed/issues/23391

Release Notes:

- Fixed a bug that sometimes caused incorrect syntax highlighting when
deploying the inline assistant.
1e1b637b50Max Brunsfeld committed on 2/17/2025, 7:20:19 PM· committed by GitHubparent69477df
2 files changedLine totals unavailable