refactor(prompts): fold Asker into Prompter and share delete confirmations

FormPrompter is the only production prompter and implements the rich
prompt API, so Ask, AskText and ConfirmDefault become the Prompter
interface and the plain Input/Confirm fallbacks go away.

Confirmations that default to no derive their non-terminal wording
from the prompt, and single deletes share deleteConfirmed for the
prompt, the request and the done line.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/prompts.go

@@ -19,6 +19,19 @@ func (a *application) confirmAction(cmd *cobra.Command, c terminal.Confirmation)
 	return terminal.ConfirmAction(cmd.Context(), c, a.options.yes, a.deps.Streams, a.policy(s), a.deps.Prompter)
 }
 
+// deleteConfirmed asks to delete subject, such as `label "bug" from alice/x`, deletes it with del
+// and reports "Deleted <subject>".
+func (a *application) deleteConfirmed(cmd *cobra.Command, subject string, del func() error) error {
+	if err := a.confirmAction(cmd, terminal.Confirmation{Prompt: "Delete " + subject + "?"}); err != nil {
+		return err
+	}
+	if err := del(); err != nil {
+		return err
+	}
+	a.done(cmd, "Deleted %s", subject)
+	return nil
+}
+
 // requireInput fills a missing value from a prompt titled label, such as "Label name", re-prompting
 // until the answer is non-empty and validate, when set, accepts it. Without prompts it returns a
 // usage error naming --flag. It reports whether it prompted.