remove extraneous text

"Basic usage" implies there is an example that shows advanced usage

Author: tshepang

alloc/src/slice.rs

@@ -493,8 +493,6 @@ impl<T> [T] {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
     /// ```

alloc/src/str.rs

@@ -246,8 +246,6 @@ impl str {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let s = "this is old";
     ///
@@ -303,8 +301,6 @@ impl str {
     ///
     /// # Examples
     ///
-    /// Basic usage:
-    ///
     /// ```
     /// let s = "foo foo 123 foo";
     /// assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));

core/src/num/nonzero.rs

@@ -551,8 +551,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// # use std::num::NonZero;
             /// #
@@ -583,8 +581,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// # use std::num::NonZero;
             /// #
@@ -612,8 +608,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Example
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(isolate_most_least_significant_one)]
             ///
@@ -644,8 +638,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Example
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(isolate_most_least_significant_one)]
             ///
@@ -676,8 +668,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// # use std::num::NonZero;
             /// #
@@ -713,8 +703,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -746,8 +734,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -775,8 +761,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -805,8 +789,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -837,8 +819,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -872,8 +852,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -907,8 +885,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -942,8 +918,6 @@ macro_rules! nonzero_integer {
             ///
             /// # Examples
             ///
-            /// Basic usage:
-            ///
             /// ```
             /// #![feature(nonzero_bitwise)]
             /// # use std::num::NonZero;
@@ -1635,8 +1609,6 @@ macro_rules! nonzero_integer_signedness_dependent_methods {
         ///
         /// # Examples
         ///
-        /// Basic usage:
-        ///
         /// ```
         /// # use std::num::NonZero;
         /// #
@@ -1666,7 +1638,6 @@ macro_rules! nonzero_integer_signedness_dependent_methods {
         ///
         /// # Examples
         ///
-        /// Basic usage:
         /// ```
         /// # use std::num::NonZero;
         /// #
@@ -1699,8 +1670,6 @@ macro_rules! nonzero_integer_signedness_dependent_methods {
         ///
         /// # Examples
         ///
-        /// Basic usage:
-        ///
         /// ```
         /// # use std::num::NonZero;
         ///
@@ -2138,8 +2107,6 @@ macro_rules! nonzero_integer_signedness_dependent_methods {
         ///
         /// # Examples
         ///
-        /// Basic usage:
-        ///
         /// ```
         /// # use std::num::NonZero;
         ///