Better format cURL headers

Break each header on a separate line with a tab.

Author: oestrich

lib/rspec_api_documentation/curl.rb

@@ -39,7 +39,7 @@ def url
 
     def headers
       super.map do |k, v|
-        "-H \"#{format_header(k, v)}\""
+        "\\\n\t-H \"#{format_header(k, v)}\""
       end.join(" ")
     end