Change lint names to plurals

src/libstd/lib.rs

@@ -135,8 +135,8 @@
 #![feature(no_std)]
 #![no_std]
 
-#![allow(trivial_cast)]
-#![allow(trivial_numeric_cast)]
+#![allow(trivial_casts)]
+#![allow(trivial_numeric_casts)]
 #![deny(missing_docs)]
 
 #[cfg(test)] extern crate test;