- for v2106 restricted the input conversion of string types to disallow
  treating verbatim strings as possible word input.
  However, it was too strict in just allowing quoted strings
  and should have also permitted '$'-sigil variables as well.

- ensure that errors for bad string -> word input conversion
  are raised from within the '>>' read operator. These were
  previously triggered during the stripping process, which
  made error tracing more difficult.