When `goto-last-point-mode' is active, the last position of point in the
buffer is saved every time point moves, so you can easily go back to it using
`goto-last-point'.

This package is a MELPA-polished version of Chris Done's one:
https://github.com/chrisdone/emacs-config/blob/master/packages/goto-last-point/goto-last-point.el