fix(python-generator): resolve directory path

The path to the directory is now completely resolved in
PythonDocumentationGenerator._namespace to prevent from empty path names
if the path is '.'. A fallback was also added for the case that the path
is '/'; the fallback value is irrelevant as the root namespace name does
not occur in the output and only the root package path can be '/'.

src/jcloud_docsgen/core/python/_core.py

@@ -1096,7 +1096,14 @@ class PythonDocumentationGenerator:
         self.kwargs = kwargs
 
     def _namespace(self, directory: pathlib.Path) -> PythonPackageNamespace:
-        namespace = PythonPackageNamespace(directory.name, [])
+        namespace = PythonPackageNamespace(
+            # fallback for the case that the path it '/'. In this case, the
+            # name would be ''. The fallback value is irrelevant; the name is
+            # only specified because PythonPackageNamespace requires
+            # specifying it. The name will not occur in the generated output.
+            directory.resolve().name or 'project',
+            [],
+        )
 
         for entry in directory.iterdir():
             if entry.is_dir():