fix an issue where an enumeration with a stream output method would
generate strings that could not be converted back to the original
enumeration value.
Fixes Issue #1258
recent changes fixed a few issues with the default_val method. The
method used the to_string, which in cases where a user supplied a
streaming operation to enumerations they could not be converted back to
the enumeration properly resulting in some errors and confusing help
output.
---------
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
f10ee369ee