docs(std): add missing closing code block fences in doc comments

library/core/src/iter/adapters/chain.rs

@@ -321,6 +321,7 @@ impl<A: Default, B: Default> Default for Chain<A, B> {
     ///
     /// // take requires `Default`
     /// let _: Chain<_, _> = mem::take(&mut foo.0);
+    /// ```
     fn default() -> Self {
         Chain::new(Default::default(), Default::default())
     }

library/core/src/num/int_macros.rs

@@ -1285,7 +1285,7 @@ macro_rules! int_impl {
         ///
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_neg();")]
-        ///
+        /// ```
         #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
         #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
         #[must_use = "this returns the result of the operation, \

library/core/src/num/uint_macros.rs

@@ -1620,7 +1620,7 @@ macro_rules! uint_impl {
         ///
         /// ```should_panic
         #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
-        ///
+        /// ```
         #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
         #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
         #[must_use = "this returns the result of the operation, \

library/core/src/ops/range.rs

@@ -836,6 +836,7 @@ pub trait RangeBounds<T: ?Sized> {
     /// assert!(!(0.0..1.0).contains(&f32::NAN));
     /// assert!(!(0.0..f32::NAN).contains(&0.5));
     /// assert!(!(f32::NAN..1.0).contains(&0.5));
+    /// ```
     #[inline]
     #[stable(feature = "range_contains", since = "1.35.0")]
     fn contains<U>(&self, item: &U) -> bool

library/core/src/ptr/mut_ptr.rs

@@ -106,6 +106,7 @@ impl<T: PointeeSized> *mut T {
     ///
     /// // This dereference is UB. The pointer only has provenance for `x` but points to `y`.
     /// println!("{:?}", unsafe { &*bad });
+    /// ```
     #[unstable(feature = "set_ptr_value", issue = "75091")]
     #[must_use = "returns a new pointer rather than modifying its argument"]
     #[inline]

library/portable-simd/crates/core_simd/src/simd/num/int.rs

@@ -58,6 +58,7 @@ pub trait SimdInt: Copy + Sealed {
     /// let sat = x.saturating_sub(max);
     /// assert_eq!(unsat, Simd::from_array([1, MAX, MIN, 0]));
     /// assert_eq!(sat, Simd::from_array([MIN, MIN, MIN, 0]));
+    /// ```
     fn saturating_sub(self, second: Self) -> Self;
 
     /// Lanewise absolute value, implemented in Rust.

library/portable-simd/crates/core_simd/src/simd/num/uint.rs

@@ -55,6 +55,7 @@ pub trait SimdUint: Copy + Sealed {
     /// let sat = x.saturating_sub(max);
     /// assert_eq!(unsat, Simd::from_array([3, 2, 1, 0]));
     /// assert_eq!(sat, Simd::splat(0));
+    /// ```
     fn saturating_sub(self, second: Self) -> Self;
 
     /// Lanewise absolute difference.