doc: fix a formatting issue in the virtio-hld
Layout of note at the end of the doc had a CSS formatting problem solved
by adding a leading sentence before the bullet list.
@@ -610,7 +610,9 @@ To use the virtio-console device, use the following virtio command::
.. note::
- - '@' : marks the port as a console port, otherwise it is a normal
+ Here are some notes about the virtio-console device:
+
+ - ``@`` : marks the port as a console port, otherwise it is a normal
virtio serial port
- stdio/tty/pty: tty capable, which means :kbd:`TAB` and :kbd:`BACKSPACE`
are supported as in regular terminals
