Ruby

• ext/dl/cptr.c (rb_dlptr_inspect, rb_dlptr_plus, rb_dlptr_minus)
  documenting +, -, inspect
• text/dl/test_cptr.rb (test_minus, test_plus, test_inspect) testing
  minus, plus, and inspect

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25675 b2dd03c8-39d4-4d8f-98ff-823fe69b080e