Add missing </div> tags in Layout API Sizing docs (TextureGroup#691)

This fixes the broken documentation here: http://texturegroup.org/docs/layout2-api-sizing.html

docs/_docs/layout2-api-sizing.md

@@ -10,7 +10,7 @@ The easiest way to understand the compound dimension types in the Layout API is
 <img src="/static/images/layout2-api-sizing.png">
 
 ## Values (`CGFloat`, `ASDimension`)
-<br>
+
 `ASDimension` is essentially a **normal CGFloat with support for representing either a point value, a relative percentage value, or an auto value**.  
 
 This unit allows the same API to take in both fixed values, as well as relative ones.
@@ -41,6 +41,8 @@ ASDimensionMake("70pt")
 ASDimensionMake(70)
 ASDimensionMakeWithPoints(70)
 </pre>
+</div>
+</div>
 
 ### Example using `ASDimension`
 
@@ -68,8 +70,10 @@ self.rightStack.style.flexBasis = ASDimensionMake(@"60%");
 self.leftStack.style.flexBasis = ASDimensionMake("40%")
 self.rightStack.style.flexBasis = ASDimensionMake("60%")
 
-horizontalStack.children = [self.leftStack, self.rightStack]]
+horizontalStack.children = [self.leftStack, self.rightStack]
 </pre>
+</div>
+</div>
 
 ## Sizes (`CGSize`, `ASLayoutSize`)
 
@@ -187,5 +191,4 @@ func layoutSpecThatFits(_ constrainedSize: ASSizeRange) -> ASLayoutSpec
 </div>
 </div>
 
-<br>
 The `constrainedSize` passed to an `ASDisplayNode` subclass' `layoutSpecThatFits:` method is the minimum and maximum sizes that the node should fit in. The minimum and maximum `CGSize`s contained in `constrainedSize` can be used to size the node's layout elements.