Doc: Use AutocompleteInput instead of SelectInput in filterToQuery examples

[leibowitz]

I believe the filterToQuery prop on ReferenceInput is passed onto the children prop as setFilter, as the doc states in this section:

The child component receives the following props from <ReferenceInput>:

• setFilter: function to call to update the filter of the request for possible values

This seems to only matter to the AutocompleteInput. But the examples all use a SelectInput, which (as far as I'm aware) doesn't do anything with it. Correct me if I'm wrong, but I guess it was meant to be using an AutocompleteInput instead.

[fzaninotto]

Thanks!