section=new links should always load in source mode, but if you have VE as your default editor, it seems they are trying to load in VE:

1. Ensure your default editor is VE, and that you aren't using two edit tabs
2. Open https://www.mediawiki.org/wiki/Gerrit/New_repositories/Requests
3. Click "Request"

You should get a wikitext editor, and never VE