revert adding space between option help

[davidism]

People reported this was inconsistent. Effort should be devoted towards a more extensible formatting system instead.

• fixes Reconsider the choice of adding a newline after multi-line option definitions #1831

Checklist:

• Add tests that demonstrate the correct behavior of the change. Tests should fail without the change.
• Add or update relevant docs, in the docs folder and in code.
• Add an entry in CHANGES.rst summarizing the change and linking to the issue.
• Add .. versionchanged:: entries in any relevant code docs.
• Run pre-commit hooks and fix any issues.
• Run pytest and tox, no tests failed.