It would be wrong to fix that with CSS. Line breaks serve 2 purposes: 1) Content, 2) Code Formatting. So, there's no way to determine whether the line break is one or the other there. As such, it's interpreted as a space in those cases.
a paragraph. And it has
But this is preformatted
I'm not sure if my spaces at the ends of the lines will be rendered here. (Most lines have no spaces.)
Try using a text editor that doesn't automatically break lines. That should solve the problem.