anchor.diff:  #endif
     val nest: numCols: int -> (Doc -> Doc)
   
  -  /// `nestBy prefix doc` renders document `doc` with given prefix added after
  -  /// line breaks.  See also: `nest`.
  +  /// `doc |> nestBy prefix` renders document `doc` with given prefix added
  +  /// after line breaks.  See also: `nest`.
   #if DOC
     ///
     /// For example
  
positive.code:   ///
    /// For example
    ///
    ///> width << txt "foo" <| fun n ->
    ///>   [txt "bar"; txt "baz"; txt "foobar"]
    ///>   |> punctuate comma
    ///>   |> vsep
  
negative.code:   ///
    /// and
    ///
    ///> txt "a" <..> txt "b" |> group
    ///
    /// renders as
    ///
  