anchor.diff:    /// onto a single line or onto multiple lines using line continuation
     /// characters.
     ///
  -  /// Given
  +  /// For example, given
     ///
     ///> let wide = txt "\\\"a\\nb\\nc\\\""
     ///> let narrow = vsep [txt "\"a\\n\""; txt "\"b\\n\""; txt "\"c\""]
  
positive.code: 
    /// Concatenates the given documents with a `linebreak` in between.  `lhs <..>
    /// rhs` is equivalent to `lhs <^> linebreak <^> rhs`.
    static member (<..>): Doc * Doc -> Doc
  
    /// Concatenates the given documents with a `softbreak` in between.  `lhs <//>
  
negative.code:   /// renders as
    ///
    ///> a b
    ///
    /// except when it wouldn't fit within the desired number of columns.
  #endif
    val group: Doc -> Doc
  
  