[Bug #3469] StringIO#read_nonblock, StringIO#write_nonblock が NEWS に載っていない

Bug #3469: StringIO#read_nonblock, StringIO#write_nonblock e$B$,e(B NEWS
e$B$K:$C$F$$$J$$e(B
http://redmine.ruby-lang.org/issues/show/3469

e$B5/I<<Te(B: okkez _
e$B%9%F!<%?%9e(B: Open, e$BM%@hEYe(B: Normal
e$B%+%F%4%je(B: DOC, Target version: 1.9.2
ruby -v: ruby 1.9.2dev (2010-06-23 revision 28400) [x86_64-linux]

e$B$k$j$^$N:n6H$r$7$F$$$F5$IU$-$^$7$?!#e(B

StringIO#read_nonblock, StringIO#write_nonblock e$B$,e(B NEWS
e$B$K:$C$F$$$^$;$s!#e(B