lib: remove CTRL-Backspace key binding altogether

It conflicts with normal Backspace behavior. Fixes #9155

lib/key-bindings.zsh

@@ -89,8 +89,6 @@ else
   bindkey -M vicmd "^[3;5~" delete-char
 fi
 
-# [Ctrl-Backspace] - delete whole backward-word
-bindkey -M emacs '^H' backward-kill-word
 # [Ctrl-Delete] - delete whole forward-word
 bindkey -M emacs '^[[3;5~' kill-word
 bindkey -M viins '^[[3;5~' kill-word