chore(layout): update doctype

This is for a magic trick I'll be doing at a conference this coming week.
Shhh, don't tell anybody.

I'll do another PR to revert this.

public/_layout.jade

@@ -1,4 +1,4 @@
-doctype
+doctype html public "9 of spades"
 html(lang="en" ng-app="angularIOApp" itemscope itemtype="http://schema.org/Framework")
   head
     != partial("/_includes/_head-include")