Hi, and welcome!
Please see the FAQ: What's a reproducible example (`reprex`) and how do I do one? Using a reprex, complete with representative data will attract quicker and more answers. This, however isn't one that requires it.
Until I switched over to using Linux for most of my work, I hadn't noticed this, because on my macOS I had a keyboard macro long installed to simply expand my abbreviations. And I was puzzled, as you are, why it works differently in the editor and console.
I was looking for somewhere to edit this and thought that the Global Options | Code | Snippets might provide a way, but no luck. Try typing
> fun
in the console and waiting for the autocomplete suggestions, and see that it doesn't work in the editor.
That leads me to think it can't be user modified.