Update Unicode escapes;

Author: bjoernager

Diff for: library/core/src/char/methods.rs

@@ -69,7 +69,7 @@ impl char {
     /// assert_eq!(char::from_u32(value_at_max + 1), None);
     /// ```
     #[stable(feature = "assoc_char_consts", since = "1.52.0")]
-    pub const MAX: char = '\u{10ffff}';
+    pub const MAX: char = '\u{10FFFF}';
 
     /// `U+FFFD REPLACEMENT CHARACTER` (�) is used in Unicode to represent a
     /// decoding error.
@@ -847,7 +847,7 @@ impl char {
     /// assert!('\n'.is_whitespace());
     ///
     /// // a non-breaking space
-    /// assert!('\u{A0}'.is_whitespace());
+    /// assert!('\u{00A0}'.is_whitespace());
     ///
     /// assert!(!'越'.is_whitespace());
     /// ```
@@ -1015,7 +1015,7 @@ impl char {
     /// Both are equivalent to:
     ///
     /// ```
-    /// println!("i\u{307}");
+    /// println!("i\u{0307}");
     /// ```
     ///
     /// Using [`to_string`](../std/string/trait.ToString.html#tymethod.to_string):
@@ -1024,7 +1024,7 @@ impl char {
     /// assert_eq!('C'.to_lowercase().to_string(), "c");
     ///
     /// // Sometimes the result is more than one character:
-    /// assert_eq!('İ'.to_lowercase().to_string(), "i\u{307}");
+    /// assert_eq!('İ'.to_lowercase().to_string(), "i\u{0307}");
     ///
     /// // Characters that do not have both uppercase and lowercase
     /// // convert into themselves.