some changes introduced by 4daa6da540, 26b6e299e1, 17898ce021 were regressed during today's merge conflict resolution of !11573.
This commit serves to reapply those changes.
/cc: @rspeicher @stanhu @mikegreiling
for posterity.
Also fix issue where destroying a Milestone would cause odd, transient messages like
"created milestone" or "imported milestone".
Add "in" preposition when creating and destroying milestones
Closes#2382