docs: Further clarify APIs

[epage]

This is a follow up to #486

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 41.84%. Comparing base (f19b064) to head (5bf8c2f).

Files	Patch %	Lines
src/ascii/mod.rs	50.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #491 +/- ## ========================================== + Coverage 41.82% 41.84% +0.01% ========================================== Files 18 18 Lines 3046 3047 +1 ========================================== + Hits 1274 1275 +1 Misses 1772 1772 ```

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[coveralls]

Pull Request Test Coverage Report for Build 8101790425

Details

• 1 of 2 (50.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.02%) to 41.844%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ascii/mod.rs	1	2	50.0%
<!--	Total:	1	2	50.0%	-->

Files with Coverage Reduction	New Missed Lines	%
src/ascii/mod.rs	1	55.51%
<!--	Total:	1		-->

Totals
Change from base Build 8101405859:	0.02%
Covered Lines:	1275
Relevant Lines:	3047

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💛 - Coveralls