/// 'Whitespace' is defined according to the terms of the Unicode Derived
/// Core Property `White_Space`.
///
+ /// # Text directionality
+ ///
+ /// A string is a sequence of bytes. 'Left' in this context means the first
+ /// position of that byte string; for a language like Arabic or Hebrew
+ /// which are 'right to left' rather than 'left to right', this will be
+ /// the _right_ side, not the left.
+ ///
/// # Examples
///
/// Basic usage:
/// 'Whitespace' is defined according to the terms of the Unicode Derived
/// Core Property `White_Space`.
///
+ /// # Text directionality
+ ///
+ /// A string is a sequence of bytes. 'Right' in this context means the last
+ /// position of that byte string; for a language like Arabic or Hebrew
+ /// which are 'right to left' rather than 'left to right', this will be
+ /// the _left_ side, not the right.
+ ///
/// # Examples
///
/// Basic usage:
///
/// [`char`]: primitive.char.html
///
+ /// # Text directionality
+ ///
+ /// A string is a sequence of bytes. 'Left' in this context means the first
+ /// position of that byte string; for a language like Arabic or Hebrew
+ /// which are 'right to left' rather than 'left to right', this will be
+ /// the _right_ side, not the left.
+ ///
/// # Examples
///
/// Basic usage:
///
/// [`char`]: primitive.char.html
///
+ /// # Text directionality
+ ///
+ /// A string is a sequence of bytes. 'Right' in this context means the last
+ /// position of that byte string; for a language like Arabic or Hebrew
+ /// which are 'right to left' rather than 'left to right', this will be
+ /// the _left_ side, not the right.
+ ///
/// # Examples
///
/// Simple patterns: