[Bug Report] Crash on Un-indentation of Spaces
### Version

Nightly

### Category

Major — The software does not fulfill the task it is designed for.

### Steps to Reproduce

1. open any file, say a new one named `test.txt`
2. switch to Insert Mode
3. insert two spaces in an empty line
4. switch to Normal Mode
5. un-indent the line with the two spaces; this will crash the editor

### Detailed Description

_No response_