Data Grid Example: Add Similar Example Links and Revise Properties Table

Modified examples/grid/dataGrids.html:
1. In the introduction, add links to layout grid and advanced data grid examples.
2. IN roles, states, and properties table, make editorial changes to rowcount and colcount rows suggested by @annabbott in issue #160.

examples/grid/dataGrids.html

@@ -35,11 +35,11 @@ <h1>Data Grid Examples</h1>
     second and third implementations add advanced features, such as content editing, sort, scroll,
     and show/hide.
   </p>
-  <p>
-    <strong>Note:</strong>
-    To see a data grid that behaves more like a typical spreadsheet and also supports features like cell and row selection,
-    see the <a href="advancedDataGrid.html">Advanced Data Grid Example.</a>
-  </p>
+  <p>Similar examples include:</p>
+  <ul>
+    <li><a href="LayoutGrids.html">Layout Grid Examples</a>: Three example implementations of grids that are used to lay out widgets, including a collection of navigation links, a message recipients list, and a set of search results.</li>
+    <li><a href="advancedDataGrid.html">Advanced Data Grid Example</a>: Example of a grid with behaviors and features similar to a typical spreadsheet, including cell and row selection.</li>
+  </ul>
   <section>
     <h2>Examples</h2>
     <section>
@@ -680,7 +680,7 @@ <h2 id="rps_label">Role, Property, State, and Tabindex  Attributes</h2>
           <td>
             <ul>
               <li>In example 3, specified because a total of 16 rows are available, but fewer
-                than 16 rows are visible to assistive technologies.</li>
+                than 16 rows are visible.</li>
               <li>
                 In this case, to demonstrate this feature, some rows are hidden using <code>display:none</code>,
                 which excludes them from the browser's accessibility tree.
@@ -703,7 +703,7 @@ <h2 id="rps_label">Role, Property, State, and Tabindex  Attributes</h2>
           <td>
             <ul>
               <li>In example 3, specified because a total of 6 columns are available, but when
-                columns are hidden, fewer than 6 columns are visible to assistive technologies.</li>
+                columns are hidden, fewer than 6 columns are visible.</li>
               <li>
                 Similar to how <code>aria-rowcount</code> overrides the browser calculation of the
                 total number of rows, the browser uses this value for the total number of columns so