Remove vim exit sequence, which has no effect

[rolandwalker]

Description

I've tried to figure this out, but the multiline exception for :q seems to have no effect. Maybe it was an in-joke?

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .

[scottnemes]

I researched python REPL as I'd never heard of it, but as best I can tell :q isn't a thing there as it is in actual vim so doesn't seem to be useful here.

[github-actions]

No correctness, security, or regression issues found in the changes.

Notes

• There’s no test coverage around _multiline_exception() behavior. If you want to guard against future regressions, consider adding a small unit test in test to assert that only actual special commands (e.g., \q, exit, quit) bypass multiline, and :q does not.

Tests not run (not requested).