Page Anchor links do not have a discernable name

[jenweber]

This markup causes a "links do not have a discernable name" error:

<h3 id="toc_introducing-ember-objects" class="anchorable-toc">
   Introducing: Ember Objects
   <a class="toc-anchor" href="#toc_introducing-ember-objects"></a>
</h3>

This fix below works to put the text inside a link, but shipping it requires changes to styling. Since the headers become proper links, they need work to make them look like normal headers again.

In guides-article.js:

    for (var element of allHeaders) {
      if (element.id) {
        element.className = 'anchorable-toc'
        let link = document.createElement('a');
        link.className = 'toc-anchor';
        link.href = `#${element.id}`;
        link.innerText = element.textContent;
        element.innerText = '';
        element.appendChild(link, element.firstElementChild);
      }
    }

Results in

<h2 id="some-text" class="anchorable-toc"><a class="toc-anchor" href="#sometext">Some Text</a></h2>

[jenweber]

This should be upstreamed to the guidemaker default template