Update H39.html (#2137)

Update to address #2136
Tighten the language of [H39 Using caption elements to associate data
table captions with data
tables](https://www.w3.org/WAI/WCAG22/Techniques/html/H39) to isolate it
to only passing 1.3.1 Info and Relationships:
1. if there is a visible text title/caption for the table, then
2. make sure it is referenced so that the title/caption is
programmaticalyy associated.

---------

Co-authored-by: Patrick H. Lauke <redux@splintered.co.uk>
Co-authored-by: Francis Storr <francis.storr@intel.com>

techniques/html/H39.html

@@ -40,15 +40,14 @@ <h2>Tests</h2>
 				<h3>Procedure</h3>
         <p>For each data table:</p>
         <ol>
-					<li>Check that the table has content that is presented as a table caption.</li>
           <li>Check that the table includes a <code class="language-html">caption</code> element.</li>
-          <li>Check that the content of the <code class="language-html">caption</code> element identifies the table.</li>
-         </ol>
+          <li>Check that the text that titles or describes the table is included in the <code class="language-html">caption</code> element.</li>
+        </ol>
       </section>
       <section class="results">
          <h3>Expected Results</h3>
          <ul>
-					<li>#1, #2, and #3 are true.</li>
+           <li>#1 and #2 are true.</li>
          </ul>
       </section>
    </section>