doc: replay: move “default” to the right-hand side

doc: replay: move “default” to the right-hand side

This is now a description list (see previous commit) and parentheticals
like this do not go on the left-hand side. Moving it to the other side
makes it stand out just as much and is also more consistent with the
rest of the documentation.

Let’s also do the same for the `replay.refAction` description list.
That makes the two desc. lists identical in the first sentence. Let’s
add a comment about that for future editors.

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>