Just use a single message

lib/rubocop/cop/github/rails_controller_render_literal.rb

@@ -9,9 +9,7 @@ module RuboCop
       class RailsControllerRenderLiteral < Base
         include RenderLiteralHelpers
 
-        MSG = "render must be used with a string literal or an instance of a Class"
-
-        LOCALS_MSG = "render must be used with a hash literal for the locals keyword argument"
+        MSG = "render must be used with a string literal or an instance of a Class, and use literals for locals keys"
 
         def_node_matcher :ignore_key?, <<-PATTERN
           (pair (sym {
@@ -101,7 +99,7 @@ module RuboCop
           if option_pairs
             locals = option_pairs.map { |pair| locals_key?(pair) }.compact.first
             if locals && (!locals.hash_type? || !hash_with_literal_keys?(locals))
-              add_offense(node, message: LOCALS_MSG)
+              add_offense(node)
             end
           end
         end