do not ignore bound completion widgets

[shadarim]

Hi,

I have some completion widgets, which I use from time to time bound in my config. Notably:
_history-complete-older
_history-complete-newer
_history_complete_word

I noticed that when I use them they insert the word from history, but also lead to the suggestion line beeing completed till the end after the inserted word. This kind of messes up what I was trying to do in the first place. So I wrote a small fix which would only add the NON-bound completion widgets (beginning with _) to the ignore_widgets array.

Seems to work nicely, so maybe you could have a look.

Thanks

BR
s.