Docs: copy/pasta left a type annotation from the IDLs in an example

sky/examples/style/hex-layout.sky

 #!mojo mojo:sky
 <import src="sky:core" as="sky"/>
 <script>
  class BeehiveLayoutManager extends sky.LayoutManager {
    function layout(width, height) {
      if (width == null)
        width = this.getIntrinsicWidth().value;
      let autoHeight = false;
      if (height == null) {
        height = 0;
@@ skipping 66 matching lines @@
          childCount += 1;
          loop.next();
        }
        if (childCount > 0)
          height = cellDim * (1/4 + Math.ceil(childCount / cellCount) * 3/4);
        else
          height = 0;
      }
      return super(height); // does the equivalent of getIntrinsicWidth() above, applying min-height etc
    }
-   function paintChildren(RenderingSurface canvas) {
+   function paintChildren(canvas) {
      let width = this.node.width;
      let cellCount = this.node.getProperty('beehive-count');
      let cellDim = width / cellCount;
      let children = this.walkChildren();
      let loop = children.next();
      while (!loop.done) {
        let child = loop.value;
        if (child.needsPaint) {
          canvas.save();
          try {
@@ skipping 70 matching lines @@
  div { display: beehive; beehive-count: 3; }
 </style>
 <div>
  <t>Hello</t>
  <t>World</t>
  <t>How</t>
  <t>Are</t>
  <t>You</t>
  <t>Today?</t>
 </div>