Fill in missing and incomplete transform

Author: wilddamon

css-typed-om/Overview.bs

@@ -764,7 +764,7 @@ Shorthand properties and values are not supported.
     <td>{{CSSKeywordValue}}</td>
   </tr>
   <tr>
-    <td>'back'</td>
+    <td>'backface-visibility'</td>
     <td>{{CSSKeywordValue}}</td>
   </tr>
   <tr>
@@ -1139,6 +1139,10 @@ Shorthand properties and values are not supported.
     <td>'transform-origin'</td>
     <td>TransformOriginValue | {{CSSKeywordValue}}</td>
   </tr>
+  <tr>
+    <td>'transform-style'</td>
+    <td>{{CSSKeywordValue}}</td>
+  </tr>
   <tr>
     <td>'unicode-bidi'</td>
     <td>{{CSSKeywordValue}}</td>