Update index.en.adoc

modules/ROOT/pages/index.en.adoc

@@ -17,13 +17,15 @@ link:https://www.ferd-net.de/standards/zugferd/index.html[ZUGFeRD]/Factur-X is a
 === C++
 * link:https://www.ghostscript.com/[Ghostscript], in it's core a C++ library,  link:https://bugs.ghostscript.com/show_bug.cgi?id=696472[can be used in a way] that it actually produced proper PDF/A-3 Factur-X
 
-#### .net/ C#
+=== .net/ C#
 * link:https://github.com/stephanstapel/ZUGFeRD-csharp[ZUGFeRD-csharp], library for .net/ C#
 
 === Java
 * link:https://konik.io/[Konik] GPL Java and C# library for ZUGFeRD 1
 * link:https://mustangproject.org/[Mustang] is an APL Java and link:https://mustangproject.org/net/[.net] library for ZUGFeRD 1 and 2(=Factur-X) and a command-line tool to extract, combine and validate. It's open-source link:https://github.com/ZUGFeRD/mustangserver[REST API] has been continued link:https://mustangproject.org/server/[commercially].
 
+=== Delphi
+* link:https://github.com/LandrixSoftware/ZUGFeRD-for-Delphi], library for Delphi
 
 == PDF tools
 === Creation