Rollup merge of rust-lang#95708 - fee1-dead:doc_whitespace_trim, r=Dylan-DPC

Update documentation for `trim*` and `is_whitespace` to include newlines

Author: Dylan-DPC

library/core/src/char/methods.rs

@@ -804,6 +804,9 @@ impl char {
     /// ```
     /// assert!(' '.is_whitespace());
     ///
+    /// // line break
+    /// assert!('\n'.is_whitespace());
+    ///
     /// // a non-breaking space
     /// assert!('\u{A0}'.is_whitespace());
     ///

library/core/src/str/mod.rs

@@ -1832,14 +1832,14 @@ impl str {
     /// Returns a string slice with leading and trailing whitespace removed.
     ///
     /// 'Whitespace' is defined according to the terms of the Unicode Derived
-    /// Core Property `White_Space`.
+    /// Core Property `White_Space`, which includes newlines.
     ///
     /// # Examples
     ///
     /// Basic usage:
     ///
     /// ```
-    /// let s = " Hello\tworld\t";
+    /// let s = "\n Hello\tworld\t\n";
     ///
     /// assert_eq!("Hello\tworld", s.trim());
     /// ```
@@ -1855,7 +1855,7 @@ impl str {
     /// Returns a string slice with leading whitespace removed.
     ///
     /// 'Whitespace' is defined according to the terms of the Unicode Derived
-    /// Core Property `White_Space`.
+    /// Core Property `White_Space`, which includes newlines.
     ///
     /// # Text directionality
     ///
@@ -1869,8 +1869,8 @@ impl str {
     /// Basic usage:
     ///
     /// ```
-    /// let s = " Hello\tworld\t";
-    /// assert_eq!("Hello\tworld\t", s.trim_start());
+    /// let s = "\n Hello\tworld\t\n";
+    /// assert_eq!("Hello\tworld\t\n", s.trim_start());
     /// ```
     ///
     /// Directionality:
@@ -1894,7 +1894,7 @@ impl str {
     /// Returns a string slice with trailing whitespace removed.
     ///
     /// 'Whitespace' is defined according to the terms of the Unicode Derived
-    /// Core Property `White_Space`.
+    /// Core Property `White_Space`, which includes newlines.
     ///
     /// # Text directionality
     ///
@@ -1908,8 +1908,8 @@ impl str {
     /// Basic usage:
     ///
     /// ```
-    /// let s = " Hello\tworld\t";
-    /// assert_eq!(" Hello\tworld", s.trim_end());
+    /// let s = "\n Hello\tworld\t\n";
+    /// assert_eq!("\n Hello\tworld", s.trim_end());
     /// ```
     ///
     /// Directionality: