Improved log message

Co-authored-by: Sadie L. Bartholomew <[email protected]>

Author: davidhassell

Changelog.rst

@@ -27,8 +27,8 @@ version 3.16.2
 * Fix bug in `cf.aggregate` that sometimes put a null transpose
   operation into the Dask graph when one was not needed
   (https://github.com/NCAS-CMS/cf-python/issues/754)
-* Fix bug in `cf.aggregate` that caused a failure when properties are
-  `numpy` arrays with two or more elements
+* Fix bug in `cf.aggregate` that caused a failure when property values
+  were `numpy` arrays with two or more elements
   (https://github.com/NCAS-CMS/cf-python/issues/764)
 * Fix bug in `cf.aggregate` that didn't correctly handle the
   "actual_range" CF attribute