chardev: Fix manual page and qemu-doc for -chardev tty

Broken in commit d59044ef.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>
Message-id: 1360767256-610-2-git-send-email-armbru@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

qemu-options.hx

@@ -1956,7 +1956,7 @@ Connect to a local BrlAPI server. @option{braille} does not take any options.
 @item -chardev tty ,id=@var{id} ,path=@var{path}
 
 @option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
-DragonFlyBSD hosts.  It is an alias for -serial.
+DragonFlyBSD hosts.  It is an alias for @option{serial}.
 
 @option{path} specifies the path to the tty. @option{path} is required.