nits

Author: AndyGauge

src/data_structures/bitfield/bitfield.md

@@ -5,7 +5,7 @@
 Creates type safe bitfield type `MyFlags` with elementary `clear` operation as well as [`Display`] trait for it.
 Subsequently, shows basic bitwise operations and formatting.
 
-```rust,edition2018
+```rust,edition2021
 use std::fmt;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -68,14 +68,15 @@ impl fmt::Display for MyFlags {
 fn main() {
     let e1 = MyFlags::FLAG_A | MyFlags::FLAG_C;
     let e2 = MyFlags::FLAG_B | MyFlags::FLAG_C;
-    assert_eq!((e1 | e2), MyFlags::FLAG_ABC);   
-    assert_eq!((e1 & e2), MyFlags::FLAG_C);    
-    assert_eq!((e1 - e2), MyFlags::FLAG_A);    
-    assert_eq!(!e2, MyFlags::FLAG_A);           
+    assert_eq!((e1 | e2), MyFlags::FLAG_ABC);
+    assert_eq!((e1 & e2), MyFlags::FLAG_C);
+    assert_eq!((e1 - e2), MyFlags::FLAG_A);
+    assert_eq!(!e2, MyFlags::FLAG_A);
 
     let mut flags = MyFlags::FLAG_ABC;
     assert_eq!(format!("{}", flags), "00000000000000000000000000000111");
     assert_eq!(format!("{}", flags.clear()), "00000000000000000000000000000000");
     assert_eq!(format!("{:?}", MyFlags::FLAG_B), "MyFlags(2)");
     assert_eq!(format!("{:?}", MyFlags::FLAG_A | MyFlags::FLAG_B), "MyFlags(3)");
 }
+```

src/hardware/processor/cpu-count.md

@@ -2,7 +2,7 @@
 
 [![num_cpus-badge]][num_cpus] [![cat-hardware-support-badge]][cat-hardware-support]
 
-Shows the number of logical CPU cores in current machine using [`num_cpus::get`].
+Shows the number of logical CPU cores in current machine using [`num_cpus::get`](https://docs.rs/num_cpus/latest/num_cpus/fn.get.html).
 
 ```rust,edition2021
 fn main() {

src/mem/global_static/lazy-constant.md

@@ -32,3 +32,22 @@ fn main() {
 ```
 
 [`HashMap`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html
+
+## Std:cell
+
+[`OnceCell`] is included in the standard library as an alternative.
+
+```rust,edition2021
+use std::cell::OnceCell;
+
+let cell = OnceCell::new();
+assert!(cell.get().is_none());
+
+let value: &String = cell.get_or_init(|| {
+    "Hello, World!".to_string()
+});
+assert_eq!(value, "Hello, World!");
+assert!(cell.get().is_some());
+```
+
+[`OnceCell`]: https://doc.rust-lang.org/beta/std/cell/struct.OnceCell.html