chore: define alt ng2 layout for top-level pages (#2686)

public/_layout.jade

@@ -1,23 +1,33 @@
-doctype html public
-html(lang="en" ng-app="angularIOApp" itemscope itemtype="http://schema.org/Framework")
-  head
-    != partial("/_includes/_head-include")
+if jade2ng
+  if hero == 'home'
+    != partial("/_includes/_hero-home")
+  else
+    != partial("/_includes/_hero")
+    != partial("../_includes/_banner")
+  - var format = autoformat ? 'docs-content' : ''
+  article(class="l-content #{format}")
+    != yield
+else
+  doctype html public
+  html(lang="en" ng-app="angularIOApp" itemscope itemtype="http://schema.org/Framework")
+    head
+      != partial("/_includes/_head-include")
 
-  body.ng-cloak.l-offset-nav(ng-controller="AppCtrl as appCtrl")
-    != partial("/_includes/_main-nav")
+    body.ng-cloak.l-offset-nav(ng-controller="AppCtrl as appCtrl")
+      != partial("/_includes/_main-nav")
 
-    <!-- HERO LOGO -->
-    if hero == 'home'
-      != partial("/_includes/_hero-home")
-    else
-      != partial("/_includes/_hero")
+      <!-- HERO LOGO -->
+      if hero == 'home'
+        != partial("/_includes/_hero-home")
+      else
+        != partial("/_includes/_hero")
 
-    - var format = autoformat ? 'docs-content' : ''
+      - var format = autoformat ? 'docs-content' : ''
 
 
-    article(class="l-content #{format}")
-      != yield
+      article(class="l-content #{format}")
+        != yield
 
-    != partial("/_includes/_footer")
-    != partial("/_includes/_scripts-include")
-    != partial("/_includes/_scripts-minimum")
+      != partial("/_includes/_footer")
+      != partial("/_includes/_scripts-include")
+      != partial("/_includes/_scripts-minimum")