Preserve selected candidate across *Completions* update

When *Completions* is updated and point was on some completion
candidate, move point to the same candidate after the update.

Also, a selected completion in *Completions* is now always
highlighted, even if it was selected by the user or other code
moving point rather than by minibuffer-next-completion, because
cursor-face-highlight-nonselected-window is now set in
completion-setup-function.

Other completion UIs (e.g. ido, vertico, etc) effectively have
this behavior: whenever they update the list of completions,
they preserve whatever candidate is selected.  This matters a
lot when completions are auto-updated, but is still useful
without auto-updating.  Including this behavior is a step
towards supporting auto-updating in the default completion UI.

* lisp/minibuffer.el (minibuffer-completion-help): Preserve the
selected completion candidate across updates. (bug#74019)
(minibuffer-hide-completions): Move point to BOB.
(minibuffer-next-completion): Don't set
cursor-face-highlight-nonselected-window.
* lisp/simple.el (completions--start-of-candidate-at)
(choose-completion): Extract the current-completion-finding code
into a separate function.
(completion-setup-function): Set
cursor-face-highlight-nonselected-window.
* etc/NEWS: Announce new behavior.

0 files changed, 0 insertions, 0 deletions