Remove invalid document of AnnotateRoutes.rewrite_contents (#727)

I removed invalid document of AnnotateRoutes.rewrite_contents.

I will add valid documents in YARD format in another PR.

Author: nard-tech

lib/annotate/annotate_routes.rb

@@ -167,7 +167,6 @@ def strip_on_removal(content, header_position)
       content
     end
 
-    # @param [String, Array<String>]
     def rewrite_contents(existing_text, new_text)
       if existing_text == new_text
         puts "#{routes_file} unchanged."