Infrastructure: Fix inconsistencies in lists of CSS and JS files on 3…

… example pages (Related to wai-aria-practices issue 255) (pull #2883)

Each example page has a list of CSS and JS files used by the sourceCode function in shared/js/examples.js. Three examples had errors in this list that are corrected by this commit. This fix supports resolution of w3c/wai-aria-practices#255, which is related to incorrect last revision dates being shown in the footer of example pages.

content/patterns/feed/examples/feed.html

@@ -192,8 +192,8 @@ <h2 id="rps_label">Role, Property, State, and Tabindex Attributes</h2>
       <section>
         <h2>JavaScript and CSS Source Code</h2>
         <p>The following Javascript and CSS is used by the feed-display.html page:</p>
-        <ul>
-          <li><a href="css/feedDisplay.css" type="tex/css">feedDisplay.css</a></li>
+        <ul id="css_js_files">
+          <li>CSS: <a href="css/feedDisplay.css" type="tex/css">feedDisplay.css</a></li>
           <li>Javascript: <a href="js/feed.js" type="text/javascript">feed.js</a>, <a href="js/feedDisplay.js" type="text/javascript">feedDisplay.js</a>, <a href="js/main.js" type="text/javascript">main.js</a>, <a href="../../../shared/js/utils.js">utils.js</a></li>
         </ul>
       </section>

content/patterns/grid/examples/advanced-data-grid.html

@@ -129,7 +129,7 @@ <h2 id="rps_label">Role, Property, State, and Tabindex Attributes</h2>
       <section>
         <h2>JavaScript and CSS Source Code</h2>
         <!--  After the js and css files are named with the name of this example, change the href and text of the following 2 links to refer to the appropriate js and css files.  -->
-        <ul>
+        <ul id="css_js_files">
           <li>
             CSS:
             <!--a href="css/example_name.css" type="tex/css">example_name.css</a-->

content/patterns/menu-button/examples/menu-button-links.html

@@ -350,7 +350,7 @@ <h2>Assistive Technology Support</h2>
       <section>
         <h2>JavaScript and CSS Source Code</h2>
 
-        <ul id="cssJsFiles">
+        <ul id="css_js_files">
           <li>CSS: <a href="css/menu-button-links.css" type="text/css">menu-button-links.css</a></li>
           <li>Javascript: <a href="js/menu-button-links.js" type="text/javascript">menu-button-links.js</a></li>
         </ul>