Fix issue where changing the case of a vim object would be clipped at the end of the line (#24163)

Co-authored-by: Conrad Irwin <conrad@zed.dev>

Closes #24124

Release Notes:

- Fixed an issue in vim mode where changing the case of an object at the
end of the line would not change the case of the last character in the
object

Co-authored-by: Conrad Irwin <conrad@zed.dev>