Update index.html

Co-authored-by: Ted Thibodeau Jr <[email protected]>

Author: pchampin

index.html

@@ -1998,7 +1998,7 @@ <h3>Algorithm</h3>
           <li>If the <var>active context</var> has a <a>default language</a> and a <a>default base direction</a>,
             set <var>default lang dir</var> to
             the concatenation of those <a>default language</a> and <a>default base direction</a>,
-            separated by an underscore (`"_"`),
+            separated by an underscore (`"_"`), and
             normalized to lower case.</li>
           <li>Otherwise, if the <var>active context</var> has a <a>default language</a>,
             set <var>default lang dir</var> to that <a>default language</a>