Call for review: small fixes to color contrast rules

Hello Act rules,

This is Call for Review for a PR making some small adjustments to the color contrast rule, refactoring applicability and improving example description. This does effectively changes a bit the Applicability (ignoring text in disabled toolbar).
https://github.com/act-rules/act-rules.github.io/pull/1978


Call for review ends on February 9th.

Jean-Yves Moyen
Principal Software Engineer


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