[Waiting for #2654] add the `\sa0` keyword to the rtf formatter

[akraus53]

This sets a default explicitly, which is set differently by some rtf displayers, e.g. MS PowerPoint. Here, \sa200 is assumed which adds a 10pt spacing after every newline, thus making the code very spaced out. For further discussion, see #1111. This issue is solved by this PR.

Edit: I referenced the wrong issue...