Fix save/restore cursor

st was assuming that save/restore cursor position was independent
of the screen that was shown in each moment, but it is not true,
because each screen has a different save/restore buffer. This
patch fixes it.
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea and freedom
500 Internal Server Error

Gitea Version: 1.28.0+dev-505-g31b4d79a84