confusion between ally and a11y in element names

[mockdeep]

A minor gripe, but I spent a while trying to understand why my dialog wasn't triggering. It turns out I had ally instead of a11y in the data attribute on the toggle button. Maybe out of scope for this project, but I thought I'd bring it up, since I can totally see myself making this mistake again in the future. It might be nice if a11y-dialog accommodated this somehow, or warned if there are ally- data attributes.

[KittyGiraudel]

Hello. That‘s fair. I improved the documentation with some clarification: f846c7c

Thanks!