more permanent fix to start codon regression

[TimothyStiles]

Changes in this PR

found a regression that was patched with #414 but needs a more permanent solution overall.

Why are you making these changes?

StartCodon handling is somewhat fuzzy.

Are any changes breaking? (IMPORTANT)

No

Pre-merge checklist

• [ ] New packages/exported functions have docstrings.
• [ ] New/changed functionality is thoroughly tested.
• [ ] New/changed functionality has a function giving an example of its usage in the associated test file. See primers/primers_test.go for what this might look like.
• [ ] Changes are documented in CHANGELOG.md in the [Unreleased] section.
• [ ] All code is properly formatted and linted.
• [ ] The PR template is filled out.

[TimothyStiles]

@carreter there's some issues with it where I had to remove some tests. Will provide more details and ask again for approval before merge.

[github-actions[bot]]

This PR has had no activity in the past 2 months. Marking as stale.

[github-actions[bot]]

This PR has had no activity in the past 2 months. Marking as stale.