Re: [PATCH v4] send-email: validate charset name in 8bit encoding prompt

> Additionally, the wording of the first prompt can confuse the user if not
> read properly or under any default assumptions for a yes/no prompt. Change
> the wording to make it explicitly clear to the user that the prompt needs a
> string input, UTF-8 being the default.
>
> The intended flow is,
>
>         Declare which 8bit encoding to use [default: UTF-8]? foobar
>         <foobar> does not appear to be a valid charset name. Use it anyway [y/N]?
>
> [1]- https://github.com/git/git/commit/852a15d748034eec87adbee73a72689c8936fb8b
>
> Signed-off-by: Shreyansh Paliwal <shreyanshpaliwalcmsmn@gmail.com>
> ---
> Changes in v4:
>  - removed the confirm_ask() helper and changes to ask().
>  - make a new warning/confirmation prompt specific to the 8bit encoding flow.