yasnippet for wl multipart

--<<alternative>>-{
--[[text/plain; charset=UTF8]]
${1:Salutations},
${2:body}
${3:Valadiction},
--
Plain text signature goes here
--[[text/html; charset=UTF8]]
$1,<br>
$2<br>
$3,<br>
--<br>
Html Signature goes here
--}-<<alternative>>