thread.c: refine stream closed message
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58286 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread.c: refine stream closed message
closed" special exception message, by explicating that it is
caused by threading. [ruby-core:80583] [Bug #13405]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58286 b2dd03c8-39d4-4d8f-98ff-823fe69b080e