Apply suggestion to docs/testing_instructions.md

docs/testing_instructions.md

@@ -6,7 +6,7 @@ some pointers on what we think would be useful to test, and guesses at what resu
 useful to write down.
 At any point please feel invited to test whatever functionality you come across, and reporting whatever you
 think is interesting. Our contact details are listed [here](https://openappstack.net/contact.html), and we'll
-descibe how to give feedback via our issue tracker at the end of this tutorial.
+descibe how to give feedback via our issue tracker at the [end of these instructions](#providing-feedback).
 
 ## Installation