Updating broken and outdated links in ARIA6 (#2358)

Closes #317

Author: fstrr

techniques/aria/ARIA6.html

@@ -2,12 +2,12 @@
       <p>Technologies that support <a href="https://www.w3.org/TR/wai-aria/">Accessible Rich Internet Applications (WAI-ARIA)</a>. </p>
    </section><section id="description"><h2>Description</h2>
       <p>The purpose of this technique is to provide a label for objects that can be read by assistive technology. The <code class="language-html">aria-label</code> attribute provides the text label for an object, such as a button. When a screen reader encounters the object, the <code class="language-html">aria-label</code> text is read so that the user will know what it is.</p>
-      <p>Authors should be aware that <code class="language-html">aria-label</code> may be disregarded by assistive technologies in situations where <code class="language-html">aria-labelledby</code> is used for the same object. For more information on the naming hierarchy please consult the <a href="https://www.w3.org/TR/wai-aria/#textalternativecomputation">ARIA specification</a> and the <a href="https://www.w3.org/TR/html-aapi/#accessible-name-and-description-calculation">accessible name and description calculation</a> in the HTML to Platform Accessibility APIs Implementation Guide. Authors should be aware that use of <code class="language-html">aria-label</code> will override any native naming such as <code class="language-html">alt</code> on images or <code class="language-html">label</code> associated with a form field using the <code class="language-html">for</code> attribute.</p>
+      <p>Authors should be aware that <code class="language-html">aria-label</code> may be disregarded by assistive technologies in situations where <code class="language-html">aria-labelledby</code> is used for the same object. For more information on the naming hierarchy please consult the <a href="https://www.w3.org/TR/accname/#mapping_additional_nd_te">accessible name and description computation</a> section of the Accessible Name And Description Computation recommendation. Authors should be aware that use of <code class="language-html">aria-label</code> will override any native naming such as <code class="language-html">alt</code> on images or <code class="language-html">label</code> associated with a form field using the <code class="language-html">for</code> attribute.</p>
    </section><section id="examples"><h2>Examples</h2>
       <section class="example">
          <h3>Distinguishing navigation landmarks</h3>
 
-            <p>The following example shows how <code class="language-html">aria-label</code> could be used to distinguish two navigation landmarks in a HTML4 and XHTML 1.0 document, where there are more than two of the same type of landmark on the same page, and there is no existing text on the page that can be referenced as the label.</p>
+            <p>The following example shows how <code class="language-html">aria-label</code> could be used to distinguish two navigation landmarks in an HTML document, where there are more than two of the same type of landmark on the same page, and there is no existing text on the page that can be referenced as the label.</p>
 <pre xml:space="preserve"><code class="language-html">&lt;div role="navigation" aria-label="Primary"&gt;
   &lt;ul&gt;
     &lt;li&gt;...a list of links here ...&lt;/li&gt;