fix(python-generator): check for module namespace

Added a check whether a module namespace with the name off a directory
already exists before adding a package namespace for the directory.

src/jcloud_docsgen/core/python/_core.py

@@ -1107,7 +1107,9 @@ class PythonDocumentationGenerator:
         )
 
         for entry in directory.iterdir():
-            if entry.is_dir():
+            if entry.is_dir() and (
+                entry.parent / (f'{entry.stem}.py')
+            ).resolve() not in [e.resolve() for e in entry.parent.iterdir()]:
                 namespace.add(self._namespace(entry))
             elif entry.suffix == '.py':
                 namespace.add(PythonModuleNamespace(entry.stem))