issue template: use input boxes

[marcoieni]

Motivations

https://github.com/babel/babel/issues/new/choose (bug report and feature request) are really cool!

If you use the input box, you don't have to deal with markdown comments.

Solution

Can we bring the input boxes in our https://github.com/rust-github/template/tree/main/.github/ISSUE_TEMPLATE ?

[marcoieni]

The "syntax for issue" is still in beta today according to the official website, so I think it's better to wait until they are stable.