anchor.diff:          let input = "</fooBar>"
           let index, value, t = eat input
           value |> should equal "fooBar"
  -        index |> should equal 8
  +        index |> should equal input.Length
           t |> should equal TagType.Close
   
       [<Test>]
  
positive.code:     let eatClosingTag01() =
          let input = "<one>ham eggs</one><two>foo bar</two>"
          let index, _, _ = eatAt input 5
          index |> should equal 18
  
      [<Test>]
      let eatClosingTag02() =
          let input = "<one>ham eggs</one>"
          let index, _, _ = eatAt input 4
          index |> should equal (input.Length - 1)
          
negative.code:         let input = "xxxx<fooBar>xxxxxxxxxx"
          let index, value, t = eat input
          value |> should equal "fooBar"
          index |> should equal 12
          t |> should equal TagType.Open
  
      [<Test>]
  