anchor.diff:      /// <returns>The result sequence.</returns>
       ///
       /// <exception cref="T:System.ArgumentNullException">Thrown when any of the input sequences is null.</exception>
  -    /// 
  +    ///
       /// <example-tbd></example-tbd>
       [<CompiledName("Zip3")>]
       val zip3: source1:seq<'T1> -> source2:seq<'T2> -> source3:seq<'T3> -> seq<'T1 * 'T2 * 'T3>
  -    
  +
       /// <summary>Return a new sequence with the item at a given index removed.</summary>
       ///
       /// <param name="index">The index of the item to be removed.</param>
       /// <param name="source">The input sequence.</param>
  -    /// 
  +    ///
       /// <returns>The result sequence.</returns>
       ///
       /// <exception cref="T:System.ArgumentException">Thrown when index is outside 0..source.Length - 1</exception>
  
positive.code:     /// <code lang="fsharp">
      /// type Foo = { Bar: string }
      ///
      /// [{Bar = "a"}; {Bar = "b"}; {Bar = "a"}]
      /// |> Seq.countBy (fun foo -> foo.Bar)
      /// </code>
      /// Evaluates to <c>seq [("a", 2); ("b", 1)]</c>
      /// </example>
  
negative.code:     /// <param name="index">The index of the item to be replaced.</param>
      /// <param name="value">The new value.</param>
      /// <param name="source">The input sequence.</param>
      ///
      /// <returns>The result sequence.</returns>
      ///
      /// <exception cref="T:System.ArgumentException">Thrown when index is outside 0..source.Length - 1</exception>
  