DOC: zarr note on encoding (#5427)

Author: raybellwaves

xarray/core/dataset.py

@@ -2001,6 +2001,10 @@ def to_zarr(
             If not other chunks are found, Zarr uses its own heuristics to
             choose automatic chunk sizes.
 
+        encoding:
+            The encoding attribute (if exists) of the DataArray(s) will be
+            used. Override any existing encodings by providing the ``encoding`` kwarg.
+
         See Also
         --------
         :ref:`io.zarr`