aria-hidden="false" is unreliable for accessibility

[hollsk]

Current Behavior

There's an aria-hidden="false" on the main #app div, where most of the page content is loaded. This doesn't work reliably in assistive technology - it's just as likely to be interpreted as aria-hidden="true" as aria-hidden="false", so in spite of your consideration, some screen reader users (or voice input users, who also rely on the accessibility tree) still may not be able to see or interact with the main content at all 😅

Steps to Reproduce

1. go to pretty much any page
2. observe the aria-hidden attribute in the #app div (class and style attributes removed for clarity): <div id="app" aria-hidden="false">

Expected Behavior

no potential for unreliability!

Screenshots

No response

Environment

• Flarum version: 1.8.5

Output of php flarum info

Output of "php flarum info", run this in terminal in your Flarum directory.

Possible Solution

The best way to treat aria-hidden is as if it were a boolean attribute instead, so when it's true, it says <div id="app" aria-hidden="true">, and when it's false it just says <div id="app">.

I'm not yet confident enough with Flarum to try submitting a pull request, but I'm hoping this is a simple enough fix that I'll be able to use it as a starter demonstration if someone is able to pick it up!

Additional Context

See the second warning note on the ARIA 2.1 spec for the aria-hidden state here (copied below): https://www.w3.org/TR/wai-aria-1.2/#aria-hidden

At the time of this writing, aria-hidden="false" is known to work inconsistently in browsers. As future implementations improve, use caution and test thoroughly before relying on this approach.