histedit: add user input to warning message on editing tagged commits

Authored by navaneeth.suresh.

Description

histedit: add user input to warning message on editing tagged commits

This is a follow-up patch to D5489.

Now, the user will be able to input yes/no(default) on the warning message. Initially, it was the sleep of 1s and histedit window opens. Changes were made as suggested by @mharbison72 and @yuja.

Differential Revision: https://phab.mercurial-scm.org/D5494