* files.el (confirm-nonexistent-file-or-buffer): Allow

* files.el (confirm-nonexistent-file-or-buffer): Allow
`after-completion' value to request confirm only after TAB.
(confirm-nonexistent-file-or-buffer): New function.
(read-buffer-to-switch, find-file, find-file-other-window)
(find-file-other-frame, find-file-read-only)
(find-file-read-only-other-window)
(find-file-read-only-other-frame): Use it.
(switch-to-buffer-other-window, switch-to-buffer-other-frame): Doc
fix.

* minibuffer.el (minibuffer-complete-and-exit): Change
`confirm-only' value of minibuffer-completion-confirm to
`confirm', and handle a `confirm-after-completion' value.