[css-text-3] Update test coverage info

Author: frivoal

css-text-3/test-coverage.html

@@ -224,7 +224,7 @@ <h3 id="tab-character-size-the-tab-size-property"><a href="https://drafts.csswg.
 <p>Missing tests
 <ul>
 	<li>No test of Animation type.
-	<li>“including its associated letter-spacing and word-spacing”
+	<li>“including its associated letter-spacing and word-spacing” (<a href="https://github.com/web-platform-tests/wpt/pull/14679">pending PR</a>)
 </ul>
 
 <h2 id="line-breaking-and-word-boundaries"><a href="https://drafts.csswg.org/css-text-3/#line-breaking">Line Breaking and Word Boundaries</a></h2>