5.44 How can I force Emacs to scroll only one line when I move past the bottom of the screen?

Customize the scroll-conservatively variable with M-x customize-variable RET scroll-conservatively RET and set it to a large value like, say, 10000. For an explanation of what this means, see Auto Scrolling in The GNU Emacs Manual.

Alternatively, use the following Lisp form in your init file (see How do I set up an init file properly?):

(setq scroll-conservatively most-positive-fixnum)