role="combobox" should be on input instead of container for better UX

[simonhermann]

The combobox role works better when used on input, e.g. VoiceOver will not say the number of entries when on container.

Observed behaviour:
when selecting an entry, VoiceOver reads "Entry 1, clickable"

Expected behaviour:
with combobox on input instead, VoiceOver reads "Entry 1, selected (1 of 10)"