herestring_redirect should be in a redirected_statement, not in a bare command

[verhovsky]

cat <<< foo

Expected:

program
  redirected_statement
    body: command
      name: command_name
        word
    redirect: herestring_redirect
      word

Actual:

program [0, 0] - [1, 0]
  command [0, 0] - [0, 11]
    name: command_name [0, 0] - [0, 3]
      word [0, 0] - [0, 3]
    redirect: herestring_redirect [0, 4] - [0, 11]
      word [0, 8] - [0, 11]