docs: use dl/dd instead of blockquote for freedesktop link

docs: use dl/dd instead of blockquote for freedesktop link

The blockquote happens to match the indentation of the other lists for
most browsers, but this isn't a guarantee. Let's instead use a
definition-list, which is more strongly connected to a list, so it's
more likely to have the same indention.

This also makes sure that we don't have similar padding on the
right-hand side, in case we change the text-size.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>