over-indenting per-line parameter list on return type annotation

[simonpercivall]

yapf 0.29
python 3.7.

When a return type annotation is added to a function definition, the parameter list gets indented an extra level:

My file test.py:

def func1(
    arg1,
    arg2,
) -> None:
    pass


def func2(
    arg1,
    arg2,
):
    pass

gets this diff (yapf -d with no extra settings):

--- test.py	(original)
+++ test.py	(reformatted)
@@ -1,6 +1,6 @@
 def func1(
-    arg1,
-    arg2,
+        arg1,
+        arg2,
 ) -> None:
     pass

I.e. only the function with the return type annotation gets the extra level.