Explicitly mention the old tech notes that were available on the Web site (and very popular)

Author: christophwille

README.md

@@ -10,6 +10,8 @@ you would expect in an IDE plus a few more.
 The #develop project started on September 11th, 2000. The project was initiated
 by Mike Krüger. In the course of the project, several contributors joined in.
 
+Looking for the tech notes (Fine Art of Commenting, Coding Style Guide, and more)? These can be found as rtf files in [doc/technotes](https://github.com/icsharpcode/SharpDevelop/tree/master/doc/technotes)
+
 ## How To Compile
  #Develop can be compiled using the supplied .bat files, or in #Develop itself.