histedit: delete to drop
The default behaviour to forbid this makes a lot of sense for novice users
because it's safeguarding them from dangerous behavior but making it
configurable will be apprieciated by power users in at least one big
organization.
It allows an user to look an histedit rules from declarative perspective and
make the rules reflect the state after histedit. If we can move lines t move
commits why can't we drop lines to drop commits?
Let's put this behind config knob and inform users about this feature the very
moment they are trying to use it so they can choose desired behaviour.