Fix build on latest nightly (#230)

Author: KernelFreeze

src/lib.rs

@@ -6,7 +6,6 @@
 #![cfg_attr(feature = "const_fn", feature(const_panic))]
 #![cfg_attr(feature = "const_fn", feature(const_mut_refs))]
 #![cfg_attr(feature = "const_fn", feature(const_fn_fn_ptr_basics))]
-#![cfg_attr(feature = "const_fn", feature(const_in_array_repeat_expressions))]
 #![cfg_attr(feature = "inline_asm", feature(asm))]
 #![cfg_attr(feature = "abi_x86_interrupt", feature(abi_x86_interrupt))]
 #![warn(missing_docs)]