Fix #14224: Correctly document args passed to function vals for title & content options of tooltips+popovers

docs/_includes/js/tooltips.html

@@ -141,7 +141,10 @@ $('#example').tooltip(options)
          <td>title</td>
          <td>string | function</td>
          <td>''</td>
-         <td>Default title value if <code>title</code> attribute isn't present</td>
+         <td>
+          <p>Default title value if <code>title</code> attribute isn't present.</p>
+          <p>If a function is given, it will be called with its <code>this</code> reference set to the element that the tooltip is attached to.</p>
+        </td>
        </tr>
        <tr>
          <td>trigger</td>