Add and apply Naming/BlockForwarding rubocop rule

This syntax has been added in Ruby 3.1.

Not using a variable name might not be very descriptive, but it's just
as descriptive as using "block" as a variable name. Using just `&` we
get the same amount of information than using `&block`: that we're
passing a block.

We're still using `&action` in `around_action` methods because here we
aren't using a generic name for the variable, so (at least for now) we
aren't running this cop on controllers using `around_action`.

lib/remote_translations/microsoft/available_locales.rb

@@ -50,7 +50,7 @@ class RemoteTranslations::Microsoft::AvailableLocales
       JSON.parse(result)["translation"].map(&:first)
     end
 
-    def self.daily_cache(key, &block)
-      Rails.cache.fetch("remote_available_locales/#{Time.current.strftime("%Y-%m-%d")}/#{key}", &block)
+    def self.daily_cache(key, &)
+      Rails.cache.fetch("remote_available_locales/#{Time.current.strftime("%Y-%m-%d")}/#{key}", &)
     end
 end