Remove flake8 ignores on blank lines
This should give better error messages than our whitespace linter, although won't touch all files.
@@ -31,8 +31,6 @@ ignore =
F403 # 'from ... import *' used; unable to detect
F405 # ... may be undefined, or defined from star
F841 # local variable ... is assigned to but never used
- W291 # trailing whitespace
- W293 # blank line contains whitespace
W504 # line break after binary operator
[tool:pytest]
