Correct property type in docs

Author: Gordon

docs/index.html

@@ -127,7 +127,7 @@ <h2>
                 </tr>
                 <tr>
                     <td><code>threshold</code></td>
-                    <td><code>Boolean</code></td>
+                    <td><code>Number</code></td>
                     <td><code>250</code></td>
                     <td>The distance in pixels before the end of the items that will trigger a call to <code>loadMore</code>.</td>
                 </tr>