Steps to replicate the issue (include links if applicable):

Add an interwiki link to any item. In the language field tap "ro" (language code for Romanian) and press Tab

What happens?: The language code becomes rmy (language code for Romani), as the first entry from the suggestion list

What should have happened instead?: If the user does not touch the suggestion list by any mean (mouse or keyboard), and the text is a valid language code, the user entry should be used.

Software version (on Special:Version page; skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):