Remove deprecation of enforce_available_locales and default it to true

CHANGELOG.md

@@ -6,3 +6,4 @@
   - Setting `:default_exception_hander` Symbol to `I18n.exception_handler`.
   - `normalize_translation_keys` in favor of `normalize_keys`.
   - `:rescue_format` option on the exception handler.
+  - `enforce_available_locales` now defaults to true with no deprecation message.

lib/i18n.rb

@@ -279,8 +279,6 @@ def locale_available?(locale)
 
     # Raises an InvalidLocale exception when the passed locale is not available.
     def enforce_available_locales!(locale)
-      handle_enforce_available_locales_deprecation
-
       if config.enforce_available_locales
         raise I18n::InvalidLocale.new(locale) if !locale_available?(locale)
       end
@@ -338,12 +336,5 @@ def normalize_key(key, separator)
     def normalized_key_cache
       @normalized_key_cache ||= Hash.new { |h,k| h[k] = {} }
     end
-
-    def handle_enforce_available_locales_deprecation
-      if config.enforce_available_locales.nil? && !defined?(@unenforced_available_locales_deprecation)
-        $stderr.puts "[deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message."
-        @unenforced_available_locales_deprecation = true
-      end
-    end
   })
 end

lib/i18n/config.rb

@@ -120,10 +120,11 @@ def load_path=(load_path)
       @@load_path = load_path
     end
 
-    # [Deprecated] this will default to true in the future
-    # Defaults to nil so that it triggers the deprecation warning
+    # Whether or not to verify if locales are in the list of available locales.
+    # Defaults to true.
+    @@enforce_available_locales = true
     def enforce_available_locales
-      defined?(@@enforce_available_locales) ? @@enforce_available_locales : nil
+      @@enforce_available_locales
     end
 
     def enforce_available_locales=(enforce_available_locales)