SLING-7167 Adjust READMEs

add uniform header linking to Sling project

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1810953 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/README.md b/README.md
index 5382c4f..c0fdcb1 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,6 @@
-Apache Sling Testing OSGi Mock
+# Apache Sling Testing OSGi Mock
+
+This module is part of the [Apache Sling](https://sling.apache.org) project.
 
 Mock implementation of selected OSGi APIs.