[ruby/stringio] Support Ractor#value

(https://github.com/ruby/stringio/pull/134)

from https://bugs.ruby-lang.org/issues/21262

We need to alias `Ractor#value` to `Ractor#take` for old versions of
Ruby.

---------

https://github.com/ruby/stringio/commit/9954dabd80

Co-authored-by: Koichi Sasada <ko1@atdot.net>
Co-authored-by: Sutou Kouhei <kou@clear-code.com>

test/stringio/test_ractor.rb

@@ -8,6 +8,10 @@ class TestStringIOInRactor < Test::Unit::TestCase
 
   def test_ractor
     assert_in_out_err([], <<-"end;", ["true"], [])
+      class Ractor
+        alias value take unless method_defined? :value # compat with Ruby 3.4 and olders
+      end
+
       require "stringio"
       $VERBOSE = nil
       r = Ractor.new do