improved type and function documentation for godoc

[github-actions[bot]]

:arrow_right: Go test coverage stayed the same at 95.2% compared to 34d8b7c9ffdb722bd35b78acf4fec99dfeab5ea8 No change in coverage for any package.

View coverage for all packages

```diff # Package Name | Coverage + github.com/mr-stringer/hanautil | 95.2% ```