proper numpydocs formatting

Author: keewis

xarray/core/options.py

@@ -183,7 +183,7 @@ class set_options:
 
     Parameters
     ----------
-    arithmetic_broadcast: bool, default: True
+    arithmetic_broadcast : bool, default: True
         Whether to perform automatic broadcasting in binary operations.
     arithmetic_compat: {"identical", "equals", "broadcast_equals", "no_conflicts", "override", "minimal"}, default: "minimal"
         How to compare non-index coordinates of the same name for potential