Add support for kwargs when delegating calls to custom loggers

Currently, when a method is called on Rails.logger, the BroadcastLogger will find the loggers that will respond to that method. However, when the method has keyword arguments, they are passed as regular arguments and will throw an ArgumentError. This adds keyword argument support by double splatting hash args.

```
class CustomLogger
  def foo(bar:)
    true
  end
end

Rails.logger.foo(bar: "baz")
```

Expected: `true`

Actual: `wrong number of arguments (given 1, expected 0) (ArgumentError)`

activesupport/lib/active_support/broadcast_logger.rb

@@ -223,15 +223,15 @@ def dispatch(&block)
         @broadcasts.each { |logger| block.call(logger) }
       end
 
-      def method_missing(name, *args, &block)
+      def method_missing(name, *args, **kwargs, &block)
         loggers = @broadcasts.select { |logger| logger.respond_to?(name) }
 
         if loggers.none?
-          super(name, *args, &block)
+          super(name, *args, **kwargs, &block)
         elsif loggers.one?
-          loggers.first.send(name, *args, &block)
+          loggers.first.send(name, *args, **kwargs, &block)
         else
-          loggers.map { |logger| logger.send(name, *args, &block) }
+          loggers.map { |logger| logger.send(name, *args, **kwargs, &block) }
         end
       end
 

activesupport/test/broadcast_logger_test.rb

@@ -278,6 +278,18 @@ def info(msg, &block)
       assert(called)
     end
 
+    test "calling a method that accepts args" do
+      logger = BroadcastLogger.new(CustomLogger.new)
+
+      assert(logger.baz("foo"))
+    end
+
+    test "calling a method that accepts kwargs" do
+      logger = BroadcastLogger.new(CustomLogger.new)
+
+      assert(logger.qux(param: "foo"))
+    end
+
     class CustomLogger
       attr_reader :adds, :closed, :chevrons
       attr_accessor :level, :progname, :formatter, :local_level
@@ -300,6 +312,14 @@ def bar
         yield
       end
 
+      def baz(param)
+        true
+      end
+
+      def qux(param:)
+        true
+      end
+
       def debug(message, &block)
         add(::Logger::DEBUG, message, &block)
       end