Add a rule for no-trailing-blank-lines for docstrings #19564
Description
Summary
Trailing blank lines within multi-line docstrings should be flagged and removed. This already happens for single-line docstrings (thanks to unnecessary-multiline-docstring), so it seems sensible to do the same for multi-line docstrings as well.
See example:
def function() -> None:
"""This single-line docstring would be fixed to remove the trailing blank lines.
"""
def function() -> None:
"""This multi-line docstring would NOT be fixed to remove the trailing blank lines.
So long as there was a second non-blank line.
"""