Specs and Docs: minor updates to fix mistakes I found when proof-reading

sky/examples/style/toolbar-layout.sky

 SKY MODULE
 <import src="sky:core" as="sky"/>
 <script>
  // display: toolbar;
  // toolbar-spacing: <length>
  // display: spring; // remaining space is split equally amongst the springs
  // children are vertically centered, layout out left-to-right with toolbar-spacing space between them
  // last child is hidden by default unless there's not enough room for the others, then it's shown last, right-aligned
  module.exports.SpringLayoutManager = class SpringLayoutManager extends sky.LayoutManager { }
  sky.registerLayoutManager('spring', module.exports.SpringLayoutManager);
  sky.registerProperty({
    name: 'toolbar-spacing',
-   type: sky.PositiveLengthStyleValueType,
+   type: sky.PositiveLengthStyleGrammar,
    inherits: true,
    initialValue: 8,
    needsLayout: true,
  });
  module.exports.ToolbarLayoutManager = class ToolbarLayoutManager extends sky.LayoutManager {
    constructor (styleNode) {
      super(styleNode);
      this.showingOverflow = false;
      this.firstSkippedChild = null;
      this.overflowChild = null;
@@ skipping 178 matching lines @@
        if (this.inChild(loop.value, x, y))
          return loop.value;
      if (this.showingOverflow)
        if (this.inChild(this.overflowChild, x, y))
          return this.overflowChild;
      return this.node;
    }
  }
  sky.registerLayoutManager('toolbar', module.exports.ToolbarLayoutManager);
 </script>