Remove std feature

Author: Christiaan676

Cargo.toml

@@ -21,7 +21,6 @@ typenum = { version = "1.17", features = ["const-generics"] }
 zeroize = { version = "1.8", optional = true, default-features = false }
 
 [features]
-std = []
 extra-sizes = []
 
 [package.metadata.docs.rs]

src/lib.rs

@@ -84,9 +84,6 @@
 //! If you have any questions, please
 //! [start a discussion](https://github.com/RustCrypto/hybrid-array/discussions).
 
-#[cfg(feature = "std")]
-extern crate std;
-
 pub mod sizes;
 
 mod from_fn;