Enable 'A' flake8 checks

Author: jwodder

tox.ini

@@ -60,7 +60,7 @@ hang-closing = False
 max-doc-length = 120
 max-line-length = 120
 unused-arguments-ignore-stub-functions = True
-select = C,B,B902,B950,E,E242,F,U100,W
+select = A,B,B902,B950,C,E,E242,F,U100,W
 ignore = B005,E203,E262,E266,E501,W503
 
 [isort]