Relations with select2: autosuggest on part of word

When the search field under "Link to" is used the search should be automatically started while typing, with wildcard

So when you type "be" it should search for "be*" and show all results starting with "be":
Beeeeh
Behehehe
Bezzzeeee

Technical analysis

• Search it on: /admin/content/?relation=keywords&limit=5&sort=title&_format=json&q=Poe
• Should be: /admin/content/?relation=keywords&limit=5&sort=title&_format=json&q=Poe*