> Is there a way to fix this while still declaring the extension packages'
> requirements?

Usually the way we expect this to work is:

- the user install prescient
- the user installs company/corfu/younameit
- it just works

Sample (and incomplete) patch below (a lot of it is unrelated,
e.g. I make it use `add-function` instead of manually saving the old
function and restoring it, and I move the "turn off the mode" to the
beginning instead of the weird recursive call which would inevitably
mess up anyone using `<foo>-prescient-mode-hook` as well as confuse
Custom's tracking of whether the mode was set (and whether pragmatically
or not)).


        Stefan