Add aria-hidden attribute + remove aria-multiselectable

[DepTrai95]

Add aria-hidden attribute + remove aria-multiselectable for better accessibility (avoid lighthouse error)

[dr-format-d]

Improvements on this pull request here: #34

[oncode]

@DepTrai95 @dr-format-d Do you have a link from W3C where they add aria-hidden? Doesn't make sense to me, since it would hide the accordion from screen readers completely.