Final call: visible-label: fix minor whitespace #1452

Hey folks,
Small update to the visible-label rule. This pull request ensures there is
a "base" passing example, before expanding on it with whitespace and case
insensitivity. This final call lasts for 1 week, until October 5th. If you
have any comments, please leave a review:

https://github.com/act-rules/act-rules.github.io/pull/1452

Kind regards,

-- 
*Wilco Fiers*
Axe-core product owner - Co-facilitator WCAG-ACT - Chair ACT-R


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