Automatically focus first autocomplete result

In order to do this space-to-complete needs to be removed too since it
doesn't work together with autofocus. I think this is a good thing
anyway as it can cause accidental selections when typing. And we already
have two other shortcuts for this too (enter and tab).

vendor/assets/javascripts/jquery-ui-autocomplete-custom.js

@@ -116,7 +116,6 @@ $.widget( "ui.autocomplete", {
           suppressKeyPress = true;
           this._keyEvent( "next", event );
           break;
-        case keyCode.SPACE:
         case keyCode.ENTER:
         case keyCode.NUMPAD_ENTER:
           // when menu is open and has focus