Update test_walker.py

kyu_3/line_safari_is_that_a_line/test_walker.py:30 in public class `WalkerClassTestCase`:
        D200: One-line docstring should fit on one line with quotes (found 3)

        The closing quotes are on the same line as the opening quotes.
        This looks better for one-liners.

kyu_3/line_safari_is_that_a_line/test_walker.py

@@ -27,9 +27,7 @@
     name='Source/Kata')
 # pylint: enable-msg=R0801
 class WalkerClassTestCase(unittest.TestCase):
-    """
-    Testing Walker class.
-    """
+    """Testing Walker class."""
     def test_starting_position_from_positives(self):
         """
         Testing Walker class.