docs: Update of tutorials and other minor fixes

Change-Id: I87d8679d38b3f17f8d4d8dbad3d5f01b3cc4ce7b
diff --git a/docs/tutorials.rst b/docs/tutorials.rst
index 1195ce6..b6e492d 100644
--- a/docs/tutorials.rst
+++ b/docs/tutorials.rst
@@ -7,4 +7,5 @@
    tutorials/security-library
    tutorials/utils-ndn-regex
    tutorials/security-validator-config
+   tutorials/signed-interest
    manpages