Untested make-completion-at-point-function capf entrypoint

* lisp/minibuffer.el (make-completion-at-point-function): New helper.
(completion-at-point-functions): Adjust docstring.
2 jobs for scratch/joaot/make-completion-at-point-function in 27 minutes and 44 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test
failed #4289
test-all

00:24:03

failed #4290
test-filenotify-gio

00:27:43

 
Name Stage Failure
failed
test-filenotify-gio Test
make[2]: *** [emacs.pdmp] Error 255
Makefile:584: recipe for target 'emacs.pdmp' failed
make[2]: Leaving directory '/builds/emacs/emacs/src'
Makefile:424: recipe for target 'src' failed
make[1]: Leaving directory '/builds/emacs/emacs'
make[1]: *** [src] Error 2
Makefile:1117: recipe for target 'bootstrap' failed
make: *** [bootstrap] Error 2
ERROR: Job failed: exit code 1
failed
test-all Test
Makefile:584: recipe for target 'emacs.pdmp' failed
make[2]: *** [emacs.pdmp] Error 255
make[2]: Leaving directory '/builds/emacs/emacs/src'
Makefile:424: recipe for target 'src' failed
make[1]: *** [src] Error 2
make[1]: Leaving directory '/builds/emacs/emacs'
Makefile:1117: recipe for target 'bootstrap' failed
make: *** [bootstrap] Error 2
ERROR: Job failed: exit code 1