Add RBS signature for Block#location

Signed-off-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

Author: Morriar

sig/types.rbs

@@ -518,7 +518,10 @@ module RBS
 
       attr_reader self_type: t?
 
-      def initialize: (type: function, ?self_type: t?, required: boolish) -> void
+      type loc = Location[bot, bot]
+      attr_reader location: loc?
+
+      def initialize: (location: loc?, type: function, ?self_type: t?, required: boolish) -> void
 
       def ==: (untyped other) -> bool