Window contents shift when toggling horizontal terminals

I migrated over to this plugin from [vim-terminal-help](https://github.com/skywind3000/vim-terminal-help) because I love switching terminals from the horizontal to floating directions on the fly. However, one difference that I noticed is that when I open/close a horizontal terminal, the contents of splits are shifted accordingly. I find this a bit distracting.

To give some more concrete information, the way that vim-terminal-help gets around this is by calling `windo winsaveview` and `windo winrestview` before and after the terminal opens/closes, respectively. That way, any shifts from opening or closing the terminal split are undone after they occur.

This seems like a simple change, so I would be happy to implement it if the shifting isn't intentional! I do wonder if the change would also make sense for the vertical layout too.