You can't. From what I've seen GTK / Gnome devs are incredibly unaccommodating to functionality that they don't agree with. https://bugzilla.gnome.org/show_bug.cgi?id=754302
The patch I'm using:
https://pastebin.com/cdkH8uXg
https://pastebin.com/Ek1tTcsm - this is 'file-chooser__typeahead.patch' which I sourced from a github somewhere