fix typo

Author: BeyondEvil

tox.ini

@@ -24,7 +24,7 @@ commands = pre-commit run --all-files --show-diff-on-failure
 [flake8]
 max-line-length = 88
 exclude = .eggs,.tox
-# rational here:
+# rationale here:
 # https://github.com/psf/black/blob/master/docs/the_black_code_style.md#slices
 extend-ignore = E203