Accessible prompter: default selections not always printed, not clear, or sometimes not readable by speech synthesis #10936

Describe the bug

Default values in the accessible prompter are not indicated and sometimes not respected at all like they are with the other prompter.

Steps to reproduce the behavior

As one example, the multi select form does not indicate which options are selected aside from the checkmarks, which as far as I can tell, are not guaranteed to be audible by speech synthesis.

Assignees
1.   ✓ BagToad

Select up to 1 options. 0 to continue.

Another example is the select form, which does not indicate the default selection at all - below if I press enter, BagToad is selected.

Repository owner
1. BagToad
<snip>
Input a number between 1 and 17: 

Another example is the text input, which has a couple issues. It displays empty parenthesis when there is no default, and displays no readable text that indicates what is being spoken is the default value.

Repository name ()

Input: 

This list is not exhaustive - we need to look through all the prompters and harmonize how we display defaults 🤔

Expected vs actual behavior

Every a11y prompt needs to display its defaults in a way that is readable by speech synthesis. Brief example:

Would you like to add a .gitignore? (default: No)

Choose [y/N]: 

☝ The change being the addition of (default: No)