fix: Prevent infinite loop while looking for package's parent folder

Issue mkdocstrings/mkdocstrings#72: mkdocstrings/mkdocstrings#472

src/griffe/finder.py

@@ -270,7 +270,7 @@ def _top_module_name(self, path: Path) -> str:
                 return top_path.name
         # if not, get the highest directory with an __init__ module,
         # add its parent to search paths and return it
-        while (parent_path.parent / "__init__.py").exists():
+        while parent_path.parent != parent_path and (parent_path.parent / "__init__.py").exists():
             parent_path = parent_path.parent
         self.search_paths.insert(0, parent_path.parent)
         return parent_path.name