Update titles

Author: Metalnem

README.md

@@ -92,9 +92,9 @@ request for the README file, or file an issue.
 - [Markdig: Markdown.ToHtml throws ArgumentOutOfRangeException](https://github.com/lunet-io/markdig/issues/275) **fixed**
 - [Markdig: Markdown.ToHtml throws IndexOutOfRangeException](https://github.com/lunet-io/markdig/issues/276) **fixed**
 - [Markdig: Markdown.ToHtml throws IndexOutOfRangeException](https://github.com/lunet-io/markdig/issues/303) **fixed**
-- [Markdig: Markdown.ToHtml throws IndexOutOfRangeException](https://github.com/xoofx/markdig/issues/839) **fixed**
-- [Markdig: Markdown.ToHtml throws IndexOutOfRangeException](https://github.com/xoofx/markdig/issues/840) **fixed**
-- [Markdig: Markdown.ToHtml throws InvalidOperationException](https://github.com/xoofx/markdig/issues/841) **fixed**
+- [Markdig: Markdown.ToHtml throws IndexOutOfRangeException for lastBlock in GetCurrentDefinitionList](https://github.com/xoofx/markdig/issues/839) **fixed**
+- [Markdig: Markdown.ToHtml throws IndexOutOfRangeException in StringSlice.NextChar()](https://github.com/xoofx/markdig/issues/840) **fixed**
+- [Markdig: Markdown.ToHtml throws InvalidOperationException "A block is already being replaced"](https://github.com/xoofx/markdig/issues/841) **fixed**
 - [Markdig: Markdown.ToHtml throws NullReferenceException](https://github.com/lunet-io/markdig/issues/277) **fixed**
 - [Markdig: StackOverflowException is throw when converting special markdown to HTML](https://github.com/xoofx/markdig/issues/497) **fixed**
 - [MarkdownSharp: Markdown.Transform hangs permanently](https://github.com/StackExchange/MarkdownSharp/issues/8)