ruff rules RET for return statements

[cclauss]

https://docs.astral.sh/ruff/rules/#flake8-return-ret

% ruff check --select=RET --ignore=RET504,RET505 --statistics

39	RET506	[*] superfluous-else-raise
14	RET508	[*] superfluous-else-break
 6	RET507	[*] superfluous-else-continue
 1	RET502	[*] implicit-return-value
Found 60 errors.
[*] 60 fixable with the `--fix` option.

% ruff check --select=RET --ignore=RET504,RET505 --fix --silent

Found 85 errors (85 fixed, 0 remaining).