Fix accessibility issue with top-level breadcrumb in ReadTheDocs theme

[micahellison]

Fixes #2827.

This fix matches the change in the upstream ReadTheDocs theme by replacing an A tag's invalid "alt" attribute with an "aria-label" attribute that screen readers can consume.

[ultrabug]

@micahellison thanks for your proposal. I'd like to ask why you think necessary to remove the support for translation of the "Docs" term to a fixed "Home" tho?

Can't you just change the alt by an aria-label while preserving the localization feature?

[micahellison]

@micahellison thanks for your proposal. I'd like to ask why you think necessary to remove the support for translation of the "Docs" term to a fixed "Home" tho?

Can't you just change the alt by an aria-label while preserving the localization feature?

Yes, that was what I did at first, though I changed it to "Home" because I had the understanding that mkdocs wants to mirror the RTD Sphinx theme, and that theme uses "Home" instead of the translation. Line 25 here: https://github.com/readthedocs/sphinx_rtd_theme/blob/master/sphinx_rtd_theme/breadcrumbs.html

I'm happy to change it back, though.