Fix bolt guide crash when using rainbow formatter

lib/bolt/application.rb

@@ -148,10 +148,8 @@ def list_groups
 
     # Show available guides.
     #
-    # @param guides [Hash] A map of topics to paths to guides.
-    # @param outputter [Bolt::Outputter] An outputter instance.
-    # @return [Boolean]
-    #
+    # @return [Hash] A map of topics of guides
+    #   Currently, the map is structured as `:topics => [Array] of guide names`
     def list_guides
       { topics: load_guides.keys }
     end

lib/bolt/outputter/human.rb

@@ -486,7 +486,7 @@ def print_plans(plans:, modulepath:)
       #
       # @param topics [Array] The available topics.
       #
-      def print_topics(topics:, **_kwargs)
+      def print_topics(topics:)
         info = +"#{colorize(:cyan, 'Topics')}\n"
         info << indent(2, topics.join("\n"))
         info << "\n\n#{colorize(:cyan, 'Additional information')}\n"

lib/bolt/outputter/json.rb

@@ -122,8 +122,8 @@ def print_result_set(result_set)
       #
       # @param topics [Array] The available topics.
       #
-      def print_topics(**kwargs)
-        print_table(kwargs)
+      def print_topics(topics:)
+        print_table({ topics: topics })
       end
 
       # Print the guide for the specified topic.

lib/bolt/outputter/rainbow.rb

@@ -104,7 +104,11 @@ def print_guide(guide, _topic)
         @stream.puts colorize(:rainbow, guide)
       end
 
-      def print_topics(topics)
+      # Print available guide topics.
+      #
+      # @param topics [Array] The available topics.
+      #
+      def print_topics(topics:)
         content  = String.new("Available topics are:\n")
         content += topics.join("\n")
         content += "\n\nUse `bolt guide <topic>` to view a specific guide."

spec/unit/outputter/rainbow_spec.rb

@@ -65,7 +65,7 @@
     CONTENT
 
     expect(outputter).to receive(:colorize).with(:rainbow, content)
-    outputter.print_topics(%w[foo bar])
+    outputter.print_topics(topics: %w[foo bar])
   end
 
   it "colorizes a message" do