feat(corfu): impl smart confirm in minibuffer

An issue when using corfu in the minibuffer was the need for pressing
RET twice, since the first only inserts the completion. This commit
aliviates that by providing C-RET to ignore completion and conclude the
minibuffer imediately and S-RET to insert completion then conclude.

modules/completion/corfu/autoload.el

@@ -1,5 +1,13 @@
 ;;; completion/corfu/autoload.el -*- lexical-binding: t; -*-
 
+;;;###autoload
+(defun +corfu-complete-and-exit-minibuffer ()
+  (interactive)
+  (if (>= corfu--index 0)
+      (corfu-complete)
+    (corfu-insert))
+  (exit-minibuffer))
+
 ;;;###autoload
 (defun +corfu-move-to-minibuffer ()
   ;; Taken from corfu's README.