editor: Prevent panics in `BlockChunks` if the block spans more than 128 lines (#38763)

Not an ideal fix, but a proper one will require restructuring the
iterator state (which would be easier if Rust had first class
generators)
Fixes ZED-1MB

Release Notes:

- N/A *or* Added/Fixed/Improved ...
9418a2f4bcLukas Wirth committed on 9/24/2025, 8:10:56 AM· committed by GitHubparent880fff4
2 files changedLine totals unavailable