Sorry for disturbing, but I did not find the answer in the docs.
I installed a MW 1.39.3 with an automated tool. Then I inserted a row into the interwiki table to make 'hu:' interwiki to recognize huwiki.
Now I write hu:anything into the search box, and get a message that I want to leave my wiki. Of course, I know, that's why I did it. What I could dig from translatewiki that the name of this message is 'gotointerwiki-external'. How could I switch this feature off and make my wiki just to go to the desired link?