$.suggestions: make it possible to re-show suggestions
This patch makes it possible to re-show suggestions after they were
hidden (by pressing Escape) by simply pressing the down arrow. This
seems to have been the intended behavior to begin with (given how
update() is called on down-arrow press when the suggestions list is
hidden), but someone borked the implementation.
To reproduce the behavior:
* type something in and wait for the suggestions to appear
* press Escape, hiding the suggestion list
* press down arrow to fetch and show it again
Change-Id: Ic8aa162d2f0701d93329de855bd8b7dbdb99f979