Defer fontification while typing

When input is pending, skip font-lock work until Emacs is idle again.
This prevents syntax highlighting from competing with keystrokes in
large or complex buffers, keeping typing smooth.  Available since
Emacs 29.

Author: bbatsov

core/prelude-editor.el

@@ -374,6 +374,10 @@ Does not indent if the mode is in `prelude-indent-sensitive-modes'."
 ;; servers and other processes that produce large output.
 (setq read-process-output-max (* 1024 1024)) ; 1MB
 
+;; defer fontification while there is input pending -- this keeps
+;; typing responsive in large/complex buffers where font-lock is slow
+(setq redisplay-skip-fontification-on-input t)
+
 ;; Compilation from Emacs
 (use-package compile
   :defer t