Screenshots:
<https://debbugs.gnu.org/cgi/bugreport.cgi?att=3;bug=41810;filename=patch1-diff-1.png;msg=20>
<https://debbugs.gnu.org/cgi/bugreport.cgi?att=4;bug=41810;filename=patch1-diff-2.png;msg=20>
<https://debbugs.gnu.org/cgi/bugreport.cgi?att=5;bug=41810;filename=patch1-nospace-1.png;msg=20>
<https://debbugs.gnu.org/cgi/bugreport.cgi?att=6;bug=41810;filename=patch1-nospace-2.png;msg=20>

2. One to only ever use spaces for positive extra-indentation: