community[patch]: docstrings (#16810)

- added missed docstrings
- formated docstrings to the consistent form

libs/community/langchain_community/document_loaders/youtube.py

@@ -141,6 +141,8 @@ def _parse_video_id(url: str) -> Optional[str]:
 
 
 class TranscriptFormat(Enum):
+    """Transcript format."""
+
     TEXT = "text"
     LINES = "lines"