[rails6] replace alias_method_chain

While using the `Module.prepend` approach is probably the correct way to
do this, the way that this class is defined is pretty gross, so I would
rather avoid trying to deal with that and simply replicate the
functionality `alias_method_chain` provided by doing two `alias_method`
calls.

This is a Gem the probably should just die anyway, so I am not terribly
bothered by the hack...

lib/jquery-rjs/rendering.rb

@@ -8,6 +8,7 @@ def render_with_update(options = {}, locals = {}, &block)
       render_without_update(options, locals, &block)
     end
   end
-
-  alias_method_chain :render, :update
-end
+
+  alias_method :render_without_update, :render
+  alias_method :render, :render_with_update
+end

lib/jquery-rjs/selector_assertions.rb

@@ -219,7 +219,8 @@ def response_from_page_with_rjs
       response_from_page_without_rjs
     end
   end
-  alias_method_chain :response_from_page, :rjs
+  alias_method :response_from_page_without_rjs, :response_from_page
+  alias_method :response_from_page, :response_from_page_with_rjs
 
   # Unescapes a RJS string.
   def unescape_rjs(rjs_string)