[rubygems/rubygems] Add notes to make sure we don't forget to backport changes to Bundler

ruby/rubygems@1ac5b14c78

Co-authored-by: André Arko <andre@arko.net>

Author: 2 people

lib/rubygems/platform.rb

@@ -163,6 +163,9 @@ def hash # :nodoc:
   # runtime platform "no version" stands for 'gnu'. To be able to disinguish
   # these, the method receiver is the gem platform, while the argument is
   # the runtime platform.
+  #
+  #--
+  # NOTE: Until it can be removed, changes to this method must also be reflected in `bundler/lib/bundler/rubygems_ext.rb`
 
   def ===(other)
     return nil unless Gem::Platform === other
@@ -186,6 +189,9 @@ def ===(other)
       )
   end
 
+  #--
+  # NOTE: Until it can be removed, changes to this method must also be reflected in `bundler/lib/bundler/rubygems_ext.rb`
+
   def normalized_linux_version
     return nil unless @version