I use a phone app called 'transit' to find out where the buses are at any moment. It's a great app for a lot of reasons, but the reason I was drawn to it at first was their witty release notes.

As the author of an R package, my release notes are much drier and businesslike. The package is quite static, so releases are mainly bug fixes. I start each item with either 'Add' or 'Change', then I name the function, and then I supply a short descriptive phrase and end with a link to the github issue where where users can see why the change was made, and what the code differences were.

I realize that this is not an answer to the question, really, because all users of the R package are basically on an even footing, in terms of knowing the R language and the science that the package is intended to support. If there is something transferrable to the OP's use-case, I guess it is to be systematic and terse, and to use a fairly fixed way of writing (being aware that not all users have English as the first language).