Revert "Call backward-kill-word instead of unix-word-rubout when C-w has been pressed."

This reverts commit 7ea3f44. We shouldn't have done this. See: #426

Author: jonathanslenders

prompt_toolkit/key_binding/bindings/basic.py

@@ -134,10 +134,9 @@ def _(event):
  handle('c-i', filter=insert_mode)(get_by_name('menu-complete'))
  handle('s-tab', filter=insert_mode)(get_by_name('menu-complete-backward'))
 
- # Control-W is bind to "unix-word-rubout" in readline by default, but
- # we bind it to backward-kill-word, because this uses word instead of
- # WORD characters as separators.
- handle('c-w', filter=insert_mode)(get_by_name('backward-kill-word'))
+ # Control-W should delete, using whitespace as separator, while M-Del
+ # should delete using [^a-zA-Z0-9] as a boundary.
+ handle('c-w', filter=insert_mode)(get_by_name('unix-word-rubout'))
 
  handle('pageup', filter= ~has_selection)(get_by_name('previous-history'))
  handle('pagedown', filter= ~has_selection)(get_by_name('next-history'))