Update the asm toolchain to 1.94.0.

Author: wt

cortex-m/asm-toolchain

@@ -1 +1 @@
-nightly-2021-12-16
+1.94.0

cortex-m/asm/lib.rs

@@ -5,8 +5,8 @@
 //! to build this file themselves.
 //!
 //! Nowadays the assembly stubs are no longer actual assembly files, but actually just this small
-//! Rust crate that uses unstable inline assembly, coupled with the `xtask` tool to invoke rustc
-//! and build the files.
+//! Rust crate that uses inline assembly, coupled with the `xtask` tool to invoke rustc and build
+//! the files.
 //!
 //! Precompiling this to a static lib allows users to call assembly routines from stable Rust, but
 //! also perform [linker plugin LTO] with the precompiled artifacts to completely inline the
@@ -21,21 +21,18 @@
 //!
 //! # Rust version management
 //!
-//! Since inline assembly is still unstable, and we want to ensure that the created blobs are
-//! up-to-date in CI, we have to pin the nightly version we use for this. The nightly toolchain is
+//! Since we want to ensure that the created blobs are up-to-date in CI, we have to
+//! pin the version of the rust toolchain that we use for this. The toolchain version is
 //! stored in `asm-toolchain`.
 //!
 //! The `cargo xtask` automation will automatically install the `asm-toolchain` as well as all
 //! Cortex-M targets needed to generate the blobs.
 //!
 //! [linker plugin LTO]: https://doc.rust-lang.org/stable/rustc/linker-plugin-lto.html
 
-#![feature(asm)]
 #![no_std]
 #![crate_type = "staticlib"]
 #![deny(warnings)]
-// Don't warn about feature(asm) being stable on Rust >= 1.59.0
-#![allow(stable_features)]
 
 mod inline;