Avoid invalid escape sequences, use raw strings (#22936)

* Avoid invalid escape sequences, use raw strings

* Integrate PR feedback

utils/check_repo.py

@@ -755,7 +755,7 @@ def find_all_documented_objects():
     for doc_file in Path(PATH_TO_DOC).glob("**/*.mdx"):
         with open(doc_file, "r", encoding="utf-8", newline="\n") as f:
             content = f.read()
-        raw_doc_objs = re.findall("\[\[autodoc\]\]\s+(\S+)\s+", content)
+        raw_doc_objs = re.findall(r"\[\[autodoc\]\]\s+(\S+)\s+", content)
         documented_obj += [obj.split(".")[-1] for obj in raw_doc_objs]
     return documented_obj