Remove superfluous latex test case and fix description

org/testdata/latex.html

@@ -1,5 +1,5 @@
 <p>
-without latex delimiters the <code class="verbatim">_{i=1}</code> and <code class="verbatim">_n</code> in <code class="verbatim">\sum_{i=1}^n a_n</code> are interpreted as subscripts.
+without latex delimiters the <code class="verbatim">_{i=1}</code> in <code class="verbatim">\sum_{i=1}^n a_n</code> is interpreted as subscript.
 we support <code class="verbatim">\(...\)</code>, <code class="verbatim">\[...\]</code>, <code class="verbatim">$$...$$</code> and <code class="verbatim">\begin{$env}...\end{$env}</code> as latex fragment delimiters.
 </p>
 <ul>
@@ -35,11 +35,4 @@ $$\sum_{i=1}^n a_n$$
 \end{xyz}
 </p>
 </li>
-<li>
-<p>
-\begin{xyz}
-foobar
-\end{xyz}
-</p>
-</li>
 </ul>