fix: one-liner quote parser does not give any output

[progsource]

Description of the change

Fixing https://github.com/progsource/maddy/issues/87

Checklist for contributor

• [x] if you want to be mentioned in the AUTHORS file, you added yourself
• [x] added an entry to CHANGELOG.md at "Upcoming"
• [x] if any Markdown definition changed, you updated the definition docs
• [x] your C++ code change is accommodated with a unit/integration test where it makes sense
• [x] your code meets the code format style (clang-format) of the project (tools/format.py)