Rollup merge of #23415 - alexcrichton:stabilize-flush, r=aturon

 The [associated RFC][rfc] for possibly splitting out `flush` has been closed and
as a result there are no more blockers for stabilizing this method, so this
commit marks the method as such.

[rfc]: https://github.com/rust-lang/rfcs/pull/950

1 files changed, 0 insertions, 1 deletions

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index f60ac8f3f33..b53bb4bc75e 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -37,7 +37,6 @@
 #![feature(staged_api)]
 #![feature(std_misc)]
 #![feature(unicode)]
-#![feature(io)]
 #![feature(path_ext)]
 
 extern crate arena;