Fix RuboCop offense Layout/EmptyLineAfterGuardClause (#38155).

git-svn-id: https://svn.redmine.org/redmine/trunk@22683 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/wiki_formatting.rb

@@ -52,6 +52,7 @@ module Redmine
         if @@formatters[name] && @@formatters[name] != entry
           raise ArgumentError, "format name '#{name}' is already taken"
         end
+
         @@formatters[name] = entry
       end