fix description of <mark>

#12956 errata

docs/_includes/css/type.html

@@ -107,7 +107,7 @@
   <!-- Inline text elements -->
   <h2 id="type-inline-text">Inline text elements</h2>
   <h3>Marked text</h3>
-  <p>For indicating blocks of text that have been deleted use the <code>&lt;mark&gt;</code> tag.</p>
+  <p>For highlighting a run of text due to its relevance in another context, use the <code>&lt;mark&gt;</code> tag.</p>
   <div class="bs-example">
     <p>You can use the mark tag to <mark>highlight</mark> text.</p>
   </div>