Update v8_09.md

Author: mythz

MyApp/_pages/releases/v8_09.md

@@ -3152,7 +3152,7 @@ GlobalRequestFilters.Add((req, res, dto) => {
 });
 ```
 
-By reverting to the use old HTML Format:
+By reverting to the use the old HTML Format:
 
 ```csharp
 ServiceStack.Templates.HtmlTemplates.HtmlFormatName = "HtmlFormatLegacy.html";