add nur/format-manifest.py reminder

quick workaround for nix-community#42

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,7 +1,11 @@
+The following points apply when adding a new repository to repos.json
+
+- [ ] I ran nur/format-manifest.py after updating `repos.json` (We will use the same script in travis ci to make sure we keep the format consistent)
 - [ ] By including this repository in NUR I give permission to license the
 content under the MIT license.
 
-Note: The license above does not apply to the packages built by the
+Clarifiction where license should apply: 
+The license above does not apply to the packages built by the
 Nix Packages collection, merely to the package descriptions (i.e., Nix
 expressions, build scripts, etc.).  It also might not apply to patches
 included in Nixpkgs, which may be derivative works of the packages to