`:universal-prefix-arg` clashes with Emacs terminology

[yuhan0]

The :universal-prefix-arg jack-in registry key introduced in #3834 is likely to confuse users, since universal-argument in Emacs is a widely understood term of art referring to '(4), '(16), etc. values (bare C-u), whereas it is used here to refer to plain integer prefix-arguments to the cider-jack-in-universal command (M-1 / C-u 1).

cider/lisp/cider-jack-in.el

Line 747 in 84800ca

- :universal-prefix-arg numeric prefix arg for `cider-jack-in-universal'.

A user attempting to customize cider-jack-in-tools (or someone like myself reading the source) may naturally misread the key as having something to do with C-u before discovering it's just a numeric dispatch slot.

Suggestion

Revert to the original :prefix-arg key name, or some other alternative eg. :dispatch-arg / :index that does not clash with existing terminology?

More drastic: switch up the naming scheme altogether for cider-jack-in-universal itself, keeping it as a deprecated alias? Although from the discussion in #3300 it seemed like a deliberate naming choice, so perhaps not (just noting the possibility)

Checking the docs, up_and_running.adoc displays this ambiguity to a minor degree - the term 'universal' is used in both senses within the same page:

Note that the universal argument C-u can be used before a command to override these settings