Rewrite :defer semantics

:defer now supports a hook, a cons cell with (SYMBOL . INTEGER) where
SYMBOL is a hook and INTEGER is a number of idle seconds before the
package is autoloaded, or just the integer (as per the default behavior
of :defer).

Also fixes an issue where switch-buffer-deffered packages (like
smartparens) wouldn't load.

modules/ui/evil-goggles/config.el

@@ -2,7 +2,7 @@
 
 (def-package! evil-goggles
   :when (featurep! :feature evil)
-  :defer input
+  :defer pre-command-hook
   :init
   (setq evil-goggles-duration 0.05
         evil-goggles-pulse nil ; too slow