remove redundant line

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

Author: davidhassell

Changelog.rst

@@ -9,7 +9,6 @@ version NEXT
   to regrid the vertical axis in logarithmic coordinates to
   `cf.Field.regrids` and `cf.Field.regridc`
   (https://github.com/NCAS-CMS/cf-python/issues/715)
-* Allow DSG tractories with identical `trajectory_id` values to be
 * Fix misleading error message when it is not possible to create area
   weights requested from `cf.Field.collapse`
   (https://github.com/NCAS-CMS/cf-python/issues/731)