Apply suggestions from code review

Author: Pierre-Sassoulas

tests/pyreverse/test_writer.py

@@ -209,9 +209,10 @@ def test_color_for_stdlib_module(default_config: PyreverseConfig) -> None:
     assert writer.get_shape_color(obj) == "grey"
 
 
-# test to check the names of the generated files are corrected
-#  when using an incorrect character like "/" in the package name
 def test_package_name_with_slash(default_config: PyreverseConfig) -> None:
+    """Test to check the names of the generated files are corrected
+    when using an incorrect character like "/" in the package name.
+    """
     writer = DiagramWriter(default_config)
     obj = Mock()