Simplify logic for adding periods onto ends of descriptions.

Remove all periods from the end of description, if there are any, and add in another one.

Author: Shammamah Hossain

dash/development/_py_components_generation.py

@@ -444,9 +444,8 @@ def create_prop_docstring(prop_name, type_object, required, description,
                 indent_spacing=indent_spacing,
                 name=prop_name,
                 type=py_type_name,
-                description=description,
-                period='. ' if description.strip()
-                and description.strip()[-1] != '.' else '',
+                description=description.strip().strip('.'),
+                period='. ',
                 is_required=is_required)
     return '{indent_spacing}- {name} ({type}' \
         '{is_required}){description}'.format(