re-export necessary types

[yxengine]

ISSUE NUMBER - PULL_REQUEST_TITLE

Fixes # (issue)

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

• The parameter type is not exported, when you want to customize the key method

List here your changes

• Re-export necessary types KeyMethod, MethodType

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)
• [x] This change requires a documentation update

Checklist

• [x] My code follows the contribution guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] My changes generate no new warnings
• [x] I formatted the code with cargo fmt
• [x] 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
• [x] 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: ...

[coveralls]

Pull Request Test Coverage Report for Build 8154243612

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.06%) to 91.917%

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Totals
Change from base Build 5472759549:	0.06%
Covered Lines:	2115
Relevant Lines:	2301

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💛 - Coveralls