Simplify likely/unlikely/cold helpers

src/utils.rs

@@ -1,23 +1,19 @@
 #[inline(always)]
-#[allow(unused)]
+#[cold]
+pub const fn cold() {}
+
+#[inline(always)]
 pub const fn likely(b: bool) -> bool {
-    // borrowed from `likely_stable` crate
-    #[allow(clippy::needless_bool)]
-    if 1_i32.checked_div(if b { 1 } else { 0 }).is_some() {
-        true
-    } else {
-        false
+    if !b {
+        cold()
     }
+    b
 }
 
 #[inline(always)]
-#[allow(unused)]
 pub const fn unlikely(b: bool) -> bool {
-    // borrowed from `likely_stable` crate
-    #[allow(clippy::needless_bool)]
-    if 1_i32.checked_div(if b { 0 } else { 1 }).is_none() {
-        true
-    } else {
-        false
+    if b {
+        cold()
     }
+    b
 }