Revert "Do wrap the 'yank' widget, because that works."

This reverts commit 8e7c26f489.

Currently, after a 'yank', paste highlighting (via $YANK_ACTIVE in zsh 5.1.1)
is applied but other highlighting (e.g., string highlighting when the yanked
text is «"foo» as a new word) is not.

See issue #183 for context.

Conflicts:
	zsh-syntax-highlighting.zsh

zsh-syntax-highlighting.zsh

@@ -182,7 +182,7 @@ _zsh_highlight_bind_widgets()
 
   # Override ZLE widgets to make them invoke _zsh_highlight.
   local cur_widget
-  for cur_widget in ${${(f)"$(builtin zle -la)"}:#(.*|_*|orig-*|run-help|which-command|beep|set-local-history)}; do
+  for cur_widget in ${${(f)"$(builtin zle -la)"}:#(.*|_*|orig-*|run-help|which-command|beep|set-local-history|yank)}; do
     case $widgets[$cur_widget] in
 
       # Already rebound event: do nothing.