Review UI docs: Move sentence about download icon to right place

The description of the download icon in the side-by-side diff view
should come directly after the description of the patch set selection
because in the UI both elements are right next to each other. The
description of the download icon got accidentally moved down by
inserting a new paragraph in [1].

[1] https://gerrit-review.googlesource.com/57014

Change-Id: I10d3b88c0a76766ba10d52a902c91c0b5dad6350
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
Review UI docs: Add screenshot of side-by-side diff with renamed file

Change-Id: I276f47b8d855db2ea1f961c172c841618ed2096e
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>