indent guides: Cache active indent range (#12204)

Caching the active indent range allows us to not re-compute the indent
range when it is not necessary

Release Notes:

- N/A
e903742d52Bennet Bo Fenner committed on 5/23/2024, 3:44:31 PM· committed by GitHubparent58a3ba0
1 file changedLine totals unavailable