Serialise some missing fields

[milliams]

Description

In #29 I added some new fields to the parser, but mistakenly missed adding them to the serialiser. This PR adds them, along with a roundtrip test.

Type of change

Please select relevant options.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• My code follows the contribution guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I formatted the code with cargo fmt
• I checked my code using cargo clippy and reports no warnings
• I have added tests that prove my fix is effective or that my feature works
• The changes I've made are Windows, MacOS, Linux compatible (or I've handled them using cfg target_os)
• I increased or maintained the code coverage for the project, compared to the previous commit

Acceptance tests

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• regression test: ...

[cocogitto-bot]

✔️ fa70400...ff9ca19 - Conventional commits check succeeded.

[coveralls]

Pull Request Test Coverage Report for Build 18191086872

Details

• 39 of 46 (84.78%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.09%) to 89.848%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/serializer.rs	18	25	72.0%

Totals
Change from base Build 18004877766:	-0.09%
Covered Lines:	2301
Relevant Lines:	2561

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💛 - Coveralls