a slash in a TD causes extra TD elements in diff

[conallcheevers]

[Test]
public void TestSlash()
{
   var oldText = "<table><tr><td> a1 n/a</td><td> b1</td></tr><tr><td> </td><td> </td></tr></table>";
   var newText = "<table><tr><td> a1</td><td> n/a</td></tr><tr><td> </td><td> </td></tr></table>";
   var output = global::HtmlDiff.HtmlDiff.Execute(oldText, newText);
   var expected = "<table><tr><td> a1<del class='diffdel'> n/a</del></td>" +
                  "<td> <del class='diffmod'>b1</del><ins class='diffmod'>n/a</ins></td></tr><tr><td> </td><td> </td></tr></table>";
   Assert.AreEqual(expected, output);
}

actual output: <table><tr><td> a1</td><td> n/a</td><td><del class='diffdel'> b1</del></td></tr><tr><td> </td><td> </td></tr></table>