'/data merge' command feedback when nothing was changed is not meaningful

The bug

When using the /data merge command without changing a value the command feedback is just "Nothing changed!". It would be better if it contained the context, so for example "The data was not changed".

How to reproduce

1. Make sure there are other entities in the world
2. Use the following command

   /data merge entity @e[type=!player,limit=1] {}