Add note to .order property

Author: dstansby

src/zarr/core/array.py

@@ -1049,6 +1049,14 @@ def order(self) -> MemoryOrder:
         -------
         bool
             Memory order of the array
+
+        Notes
+        -----
+        For Zarr format 2 arrays this is the memory order in which
+        data is stored and returned when read in to a NumPy array.
+
+        For Zarr format 3 arrays this is just the memory order
+        in which data is returned when read into a NumPy array.
         """
         if self.metadata.zarr_format == 2:
             return self.metadata.order