[A11Y] Add aria-label and landmark role to search input (#2669)
[A11Y] Add aria-label and landmark role to search input (#2669)

* Adds role="search" to Search container
* Add aria-label to search input

See this page for more info:
https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/Search_role
flarum/core,flarum/core,flarum/core