Doc: Strip trailing whitespace in pydoc_topics (GH-130492)

(cherry picked from commit 3f3e1c4)

Co-authored-by: Adam Turner <[email protected]>

Author: AA-Turner

Doc/tools/extensions/pydoc_topics.py

@@ -142,7 +142,8 @@ def write_documents(self, _docnames: Set[str]) -> None:
                 document.append(doc_ids[label_id])
                 visitor = TextTranslator(document, builder=self)
                 document.walkabout(visitor)
-                self.topics[topic_label] = visitor.body
+                body = "\n".join(map(str.rstrip, visitor.body.splitlines()))
+                self.topics[topic_label] = body
 
     def finish(self) -> None:
         topics_repr = "\n".join(