Restructured text fixes so that pydoctor would return without an error

tests/utilities/__init__.py

@@ -12,7 +12,8 @@ from collections.abc import Hashable
 class SizedIterableHashable(Iterable[Hashable], Protocol):
     """A protocol for sized iterable of hashable objects"""
 
-    def __len__(self) -> int: ...
+    def __len__(self) -> int:
+        """Add a len function to protocol so Python knows the object is sized."""
 
 
 def assert_unique_of_length(data: SizedIterableHashable, length: int) -> None:

tests/utilities/scan_test_helpers.py

@@ -91,7 +91,6 @@ def interp_closed_path(xy_points: list[tuple[int, int]], n_points: int) -> MatPa
     Modified from:
     https://stackoverflow.com/questions/33962717/interpolating-a-closed-curve-using-scipy
     """
-
     # Use zip to seperate x and y points into tuples
     x, y = zip(*xy_points)