Make FilterBlock inner class of Kemal::FilterHandler

src/kemal/filter_handler.cr

@@ -7,7 +7,7 @@ module Kemal
 
     # This middleware is lazily instantiated and added to the handlers as soon as a call to `after_X` or `before_X` is made.
     def initialize
-      @tree = Radix::Tree(Array(Kemal::FilterBlock)).new
+      @tree = Radix::Tree(Array(FilterBlock)).new
       Kemal.config.add_filter_handler(self)
     end
 
@@ -69,7 +69,6 @@ module Kemal
     private def radix_path(verb, path, type : Symbol)
       "#{type}/#{verb}/#{path}"
     end
-  end
 
     # :nodoc:
     class FilterBlock
@@ -84,3 +83,4 @@ module Kemal
       end
     end
   end
+end