Remove some use of unstable features that's meh

Signed-off-by: Alex Saveau <[email protected]>

src/generator.rs

@@ -365,8 +365,7 @@ fn print_stats(GeneratorStats { files, dirs, bytes }: GeneratorStats, output: &m
 
 #[cfg_attr(feature = "tracing", tracing::instrument(level = "trace"))]
 fn run_generator(config: Configuration) -> Result<GeneratorStats, Error> {
-    let parallelism =
-        thread::available_parallelism().unwrap_or(const { NonZeroUsize::new(1).unwrap() });
+    let parallelism = thread::available_parallelism().unwrap_or(NonZeroUsize::new(1).unwrap());
     let mut runtime = tokio::runtime::Builder::new_current_thread();
     #[cfg(all(not(miri), target_os = "linux"))]
     runtime.on_thread_start(|| {

src/lib.rs

@@ -1,6 +1,4 @@
 #![feature(let_chains)]
-#![feature(const_option)]
-#![feature(inline_const)]
 
 pub use generator::*;
 

src/utils/file_names.rs

@@ -53,8 +53,7 @@ pub fn with_file_name<T>(i: u64, f: impl FnOnce(&str) -> T) -> T {
 pub fn with_dir_name<T>(i: usize, f: impl FnOnce(&str) -> T) -> T {
     const SUFFIX: &str = ".dir";
     with_file_name(i.try_into().unwrap(), |s| {
-        #[allow(clippy::assertions_on_constants)]
-        const { assert!(usize::BITS <= 128, "Unsupported usize width.") }
+        const _: () = assert!(usize::BITS <= 128, "Unsupported usize width.");
         let mut buf = [MaybeUninit::<u8>::uninit(); 39 + SUFFIX.len()]; // 39 to support u128
 
         unsafe {