diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 83f8fd25b50..20dd95a3a46 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -89,8 +89,6 @@ pub trait Iterator {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     ///
@@ -249,8 +247,6 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     /// assert_eq!(a.iter().count(), 3);
@@ -280,8 +276,6 @@ fn count(self) -> usize
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     /// assert_eq!(a.iter().last(), Some(&3));
@@ -324,8 +318,6 @@ fn some<T>(_: Option<T>, x: T) -> Option<T> {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// #![feature(iter_advance_by)]
     ///
@@ -432,8 +424,6 @@ fn nth(&mut self, n: usize) -> Option<Self::Item> {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [0, 1, 2, 3, 4, 5];
     /// let mut iter = a.iter().step_by(2);
@@ -1342,8 +1332,6 @@ fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     ///
@@ -1434,8 +1422,6 @@ fn take(self, n: usize) -> Take<Self>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3, 4];
     ///
@@ -1486,8 +1472,6 @@ fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let words = ["alpha", "beta", "gamma"];
     ///
@@ -1765,8 +1749,6 @@ fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// // an iterator which alternates between Some and None
     /// struct Alternate {
@@ -1911,8 +1893,6 @@ fn inspect<F>(self, f: F) -> Inspect<Self, F>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let mut words = ["hello", "world", "of", "Rust"].into_iter();
     ///
@@ -2221,8 +2201,6 @@ fn collect_into<E: Extend<Self::Item>>(self, collection: &mut E) -> &mut E
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     ///
@@ -3193,8 +3171,6 @@ fn check<T>(
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     /// let b: Vec<u32> = Vec::new();
@@ -3232,8 +3208,6 @@ fn max(self) -> Option<Self::Item>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     /// let b: Vec<u32> = Vec::new();
@@ -3420,8 +3394,6 @@ fn rev(self) -> Rev<Self>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [(1, 2), (3, 4), (5, 6)];
     ///
@@ -3458,8 +3430,6 @@ fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     ///
@@ -3538,8 +3508,6 @@ fn cloned<'a, T: 'a>(self) -> Cloned<Self>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     ///
@@ -3624,8 +3592,6 @@ fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let a = [1, 2, 3];
     /// let sum: i32 = a.iter().sum();
@@ -3703,8 +3669,6 @@ fn cmp<I>(self, other: I) -> Ordering
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// #![feature(iter_order_by)]
     ///
@@ -3790,8 +3754,6 @@ fn partial_cmp<I>(self, other: I) -> Option<Ordering>
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// #![feature(iter_order_by)]
     ///
@@ -3863,8 +3825,6 @@ fn eq<I>(self, other: I) -> bool
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// #![feature(iter_order_by)]
     ///