Invert exposed ore logic

[Astrashh]

Pull Request

Description

Some users in discord have been reporting ore not being visible, have not inspected this in game yet due to dev launch being borked but going to assume reports are valid and the issue is caused by flipped method boolean return.

Changelog

• [x] (Hopefully) fixes ore exposure logic
• [x] Small refactor to improve code readability

Checklist

Mandatory checks

• [x] The base branch of this PR is an unreleased version branch (that has a ver/ prefix) or is a branch that is intended to be merged into a version branch.
• [x] There are no already existing PRs that provide the same changes.
• [x] The PR is within the scope of Terra (i.e. is something a configurable terrain generator should be doing).
• [x] Changes follow the code style for this project.
• [x] I have read the CONTRIBUTING.md document in the root of the git repository.

Types of changes

• [x] Bug Fix
• [ ] Build system
• [ ] Documentation
• [ ] New Feature
• [ ] Performance
• [x] Refactoring
• [ ] Repository
• [ ] Revert
• [ ] Style
• [ ] Tests
• [ ] Translation

Compatibility

• [ ] Introduces a breaking change
• [ ] Introduces new functionality in a backwards compatible way.
• [x] Introduces bug fixes

Documentation

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

Testing

• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

Licensing

• [x] I am the original author of this code, and I am willing to release it under GPLv3.
• [ ] I am not the original author of this code, but it is in public domain or released under GPLv3 or a compatible license.