Update docs in defaults.ini

defaults.ini

@@ -1,13 +1,20 @@
 # Default configuration settings for Rophako - DO NOT EDIT THIS FILE!
 #
-# To configure your site, create a new file named "settings.yml" and override
-# settings defined in this file. Your settings.yml is masked on top of the
-# settings in defaults.yml.
+# To configure your site, create a new file named "settings.ini" and override
+# settings defined in this file. Your settings.ini is masked on top of the
+# settings in defaults.ini.
 #
 # String values can substitute the following special variables:
 #   %(_basedir): The absolute path to the root of this git repository, such that
 #               ./rophako/app.py exists.
 #   %(_year):    inserts the current year (for the RSS feed copyright setting)
+#
+# You can also define custom global variables in the [DEFAULT] section.
+# Variables in this section are injected into ALL other sections, so it's
+# recommended to prefix these with an underscore to avoid any conflicting names.
+#
+# See the Python documentation for ConfigParser if you have any questions
+# on the syntax of this file.
 
 # Constants that may be useful in this file.
 [DEFAULT]