Fix method signature

Author: Watson1978

sig/ilios.rbs

@@ -16,8 +16,8 @@ module Ilios
 
     class Statement
       def bind: (Hash[Symbol, untyped] | Hash[String, untyped]) -> self
-      def page_size: (Integer) -> self
-      def idempotent: (true | false) -> self
+      def page_size=: (Integer) -> self
+      def idempotent=: (true | false) -> self
     end
 
     class Future