HtmlUtil.FIxInvalidTag: Better solution to handle empty tags

        [TestMethod]
        [DataRow("Foo<i></i>bar")]
        [DataRow("Foo<i>    </i>bar")]
        [DataRow("<i>Foo</i>    <i>bar</i>", "<i>Foobar</i>")]
        // [DataRow("Foo<b>    </b>bar")]
        // [DataRow("Foo<u>    </u>bar")]
        // [DataRow("Foo<font color=\"#808080\"> </font>bar")]
        // [DataRow("Foo<font color=\"#808080\"></font>bar")]
        public void FixInvalidItalicEmptyTagTest(string input, string expected = "Foobar")
        {
            Assert.AreEqual(expected, HtmlUtil.FixInvalidItalicTags(input));
        }


...............


// <i>foo</i><i>bar</i> => <i>foobar</i>
            // <i>foo</i> <i>bar</i> => <i>foo bar</i>
            // text = text.Replace("</i><i>", string.Empty); (handle bellow)
            text = text.Replace("</i> <i>", " ");

            var l = 0;
            var closeCount = 0;
            for (var r = 0; r < text.Length; r++)
            {
                if (text[r] == '<' && text[l] != '<')
                {
                    l = r;
                }
                else if (text[r] == '>' && text[l] == '<' && ++closeCount == 2)
                {
                    var st = new StrippableText(text.Substring(l, r - l + 1));

                    // no formattable text in between the tags e.g: ...<i> </i>...
                    if (string.IsNullOrWhiteSpace(st.StrippedText) &&
                        st.OriginalText.EndsWith("<i>", StringComparison.Ordinal) &&
                        st.OriginalText.StartsWith("</i>", StringComparison.Ordinal))
                    {
                        text = text.Remove(l, r - l + 1);
                        r = l - 1;
                        closeCount = 0;
                    }
                    else
                    {
                        // start counting from the last found tag
                        // For example in "<i>Foo</i>    <i>bar</i>" Skip first tag
                        l = text.LastIndexOf('<', r - 1);
                        closeCount -= 1;
                    }
                }
            }

            return preTags + text;
        }