Fix typo and improve error message in ripple writer

[ericpre]

Progress of the PR

• [x] Fix typo and improve error message in ripple writer,
• [n/a] update docstring (if appropriate),
• [n/a] update user guide (if appropriate),
• [x] add a changelog entry in the upcoming_changes folder (see upcoming_changes/README.rst),
• [x] Check formatting of the changelog entry (and eventual user guide changes) in the docs/readthedocs.org:rosettasciio build of this PR (link in github checks)
• [n/a] add tests,
• [x] ready for review.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.23%. Comparing base (46c5c5b) to head (09ce2ac).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #251 +/- ## ========================================== - Coverage 86.36% 86.23% -0.14% ========================================== Files 83 83 Lines 10652 10653 +1 Branches 2322 2322 ========================================== - Hits 9200 9187 -13 - Misses 935 949 +14 Partials 517 517 ```

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