Use separate attrs for select and text form field to help with accessibility

[KunjPrasad]

I am using PhoneNumberPrefixWidget (link). I want to provide different widget attributes for phone country code select and phone number text fields. A primary goal is to provide different aria-label attributes for the two input type because I'm unable to identify how to put different label for each and position it side by side since it is a MultiWidget. Not sure if there are alternate ways to make it accessible.

Looking at other example of MultiWidget in Django (like, here), it seems that different attrs kwargs are defined.

[francoisfreitag]

Should have been resolved with #502.