Fix several codes for clean and readable code

Author: supercaracal

lib/redis/cluster.rb

@@ -116,7 +116,7 @@ def fetch_cluster_info!(option)
       [Node.new(option.per_node_key, node_flags, option.use_replica?),
        Slot.new(available_slots, node_flags, option.use_replica?)]
     ensure
-      node&.map(&:disconnect)
+      node&.each(&:disconnect)
     end
 
     def fetch_command_details(nodes)

lib/redis/cluster/option.rb

@@ -80,7 +80,7 @@ def parse_node_option(addr)
       def add_common_node_option_if_needed(options, node_opts, key)
         return options if options[key].nil? && node_opts.first[key].nil?
 
-        options[key] = options[key] || node_opts.first[key]
+        options[key] ||= node_opts.first[key]
       end
     end
   end