chore: add ast-grep rule to convert Optional[T] to T | None (#25560)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/core/rag/extractor/helpers.py

@@ -1,17 +1,17 @@
 """Document loader helpers."""
 
 import concurrent.futures
-from typing import NamedTuple, Optional, cast
+from typing import NamedTuple, cast
 
 
 class FileEncoding(NamedTuple):
     """A file encoding as the NamedTuple."""
 
-    encoding: Optional[str]
+    encoding: str | None
     """The encoding of the file."""
     confidence: float
     """The confidence of the encoding."""
-    language: Optional[str]
+    language: str | None
     """The language of the file."""