Various changes to get ARIA 1.1 compatibility.

[anemirovsky]

Add support for ARIA 1.1 per https://www.w3.org/TR/wai-aria-1.1/#combobox.

This pull request includes a

• [ ] Bug fix
• [x] New feature
• [ ] Translation

The following changes were made

• "combobox" role attribute added to the wrapper
• "aria-haspopup" changed from "true" (which means "menu") to "listbox" to correctly match the role of the element containing the options
• "aria-activedescendant" removed from the combobox element so it appears just on the element with the "textbox" role
• "aria-multiline" set to "false" for the textbox element
• "aria-owns" switched to "aria-controls" on the textbox element