Switch disabled? to not mutate output

lib/liquid/block_body.rb

@@ -154,7 +154,10 @@ module Liquid
     private
 
     def render_node(context, output, node)
-      return if node.disabled?(context, output)
+      if node.disabled?(context)
+        output << node.disabled_error_message
+        return
+      end
       disable_tags(context, node.disabled_tags) do
         node.render_to_output_buffer(context, output)
       end

lib/liquid/tag.rb

@@ -46,10 +46,8 @@ module Liquid
       ''
     end
 
-    def disabled?(context, output)
-      if context.registers['disabled_tags'].disabled?(tag_name)
-        output << disabled_error_message
-      end
+    def disabled?(context)
+      context.registers['disabled_tags'].disabled?(tag_name)
     end
 
     def disabled_error_message

lib/liquid/variable.rb

@@ -104,7 +104,7 @@ module Liquid
       output
     end
 
-    def disabled?(_context, _output)
+    def disabled?(_context)
       false
     end