Fix _find comment format (#669)

It is showing incorrectly on web - missing break line

Author: cartond

s3fs/core.py

@@ -737,6 +737,7 @@ async def _glob(self, path, **kwargs):
     async def _find(self, path, maxdepth=None, withdirs=None, detail=False, prefix=""):
         """List all files below path.
         Like posix ``find`` command without conditions
+
         Parameters
         ----------
         path : str