Undo/Redo should alert some areas when they happen

[windymilla]

Past windy wrote in GG1:

# Override TextUndo::undo and redo so we can flag it to any routines that need to know
sub undo {
    my ($self) = @_;
    $self->SUPER::undo();
    ::errorcheckillosnupdateneeded();
}

sub redo {
    my ($self) = @_;
    $self->SUPER::redo();
    ::errorcheckillosnupdateneeded();
}

Future windy could do something similar.