Add units if "unit" is in the attrs. (pydata#4850)

Author: Illviljan

xarray/plot/utils.py

@@ -460,6 +460,8 @@ def label_from_attrs(da, extra=""):
 
     if da.attrs.get("units"):
         units = " [{}]".format(da.attrs["units"])
+    elif da.attrs.get("unit"):
+        units = " [{}]".format(da.attrs["unit"])
     else:
         units = ""