SLING-7167 Adjust READMEs

add uniform header linking to Sling project

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1810941 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/post-servlet-extensions/README.md b/post-servlet-extensions/README.md
index c81b14c..0e0bdaf 100644
--- a/post-servlet-extensions/README.md
+++ b/post-servlet-extensions/README.md
@@ -1,4 +1,6 @@
-Apache Sling Sample Post Servlet Extensions
+# Apache Sling Sample Post Servlet Extensions
+
+This module is part of the [Apache Sling](https://sling.apache.org) project.
 
 This bundle provides sample OSGI services which extend the sling post 
 servlet behaviour.