Auto merge of #26261 - tshepang:more-brief-example, r=huonw

Also, it feels more suitable to use hex to represent unicode

Author: bors

src/libcore/char.rs

@@ -74,17 +74,8 @@ pub const MAX: char = '\u{10ffff}';
 /// ```
 /// use std::char;
 ///
-/// let c = char::from_u32(10084); // produces `Some(❤)`
-/// assert_eq!(c, Some('❤'));
-/// ```
-///
-/// An invalid character:
-///
-/// ```
-/// use std::char;
-///
-/// let none = char::from_u32(1114112);
-/// assert_eq!(none, None);
+/// assert_eq!(char::from_u32(0x2764), Some('❤'));
+/// assert_eq!(char::from_u32(0x110000), None); // invalid character
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]