Update unstable attr to reference tracking issue.

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 3becc0a0c9ee17ca1886823e0ad87c0cb2c02ce0..73105640cd26b23bf376129fcdfe89a2fe21d229 100644 (file)
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -1520,7 +1520,7 @@ pub fn limit(&self) -> u64 { self.limit }
     /// # Ok(())
     /// # }
     /// ```
-    #[unstable(feature = "io_take_into_inner", issue = "0")]
+    #[unstable(feature = "io_take_into_inner", issue = "23755")]
     pub fn into_inner(self) -> T {
         self.inner
     }