dangerfile, makefile: add documentation links, intentation fixes

Dangerfile

@@ -1,3 +1,6 @@
+# Danger CI configuration file
+# https://danger.systems/guides/getting_started.html
+
 # Check for changes to README.md
 has_readme_changes = git.modified_files.include?("README.md")
 
@@ -8,7 +11,7 @@ fail 'Please provide a summary in the Pull Request description' if github.pr_bod
 warn 'Please check PR guidelines and check the boxes.' if github.pr_body.include? '- [ ]'
  
 # Warn if pull request is not updated
-warn 'Please update the Pull Request title to contain the script name' if github.pr_title.include? 'Update README.md'
+warn 'Please provide a descriptive title for the Pull Request' if github.pr_title.include? 'Update README.md'
 
 # Warn when there are merge commits in the diff
 warn 'Please rebase to get rid of the merge commits in this Pull Request' if git.commits.any? { |c| c.message =~ /^Merge branch 'master'/ }