Merge pull request #518 from Firkraag/master

Add a paragraph to explain the reason of the message "unable to load configuration from..."

Configuration.rst

@@ -36,6 +36,13 @@ uWSGI supports loading configuration files over several methods other than simpl
   uwsgi --yaml fd://0 # file descriptor
   uwsgi --json 'exec://nc 192.168.11.2:33000' # arbitrary executable
 
+.. note::
+
+  If the configuration file type is not specified in the parameter list (e.g. --ini, --xml, etc.),
+  uwsgi tries to deduce the file type from the filename extension.
+  If the extension is not a supported file type,
+  uwsgi displays the message "unable to load configuration from..." and exits.
+
 .. note::
 
   More esoteric file sources, such as the :doc:`Emperor<Emperor>`, embedded