`unnecessary-pass` is now also emitted when a function or class contains
only docstring and pass statement, in which case, docstring is enough for
empty definition.
fix sphinx-build error
* Add new check misplaced-format-function.
check only w.r.t print function.
For other use cases no-member check already exists.
fix code block not visible for few checkers
This works because execution of the lambda code is
typically deferred until the class definition is built.
Also avoid suppression for default arguments of lambda's
if the class scope is the immediate parent scope
of the lambda.
Close#704
