a11y improvements

[jenweber]

An effort to rehabilitate #26

[jenweber]

Any changes made to styling in this issue/PR also need to go in ember-learn/ember-cli-tutorial-style#2

I'll keep the alt tag improvements, label for, and the styling. I'll write a quick blurb about alt, use the Tomster/Zoey says to suggest ember-a11y while explaining labels, and just silently update the styling. I'll include only ember-a11y-testing in the super-rentals app, but only for tests. (I'll skip focusing-outlet)

[luxzeitlos]

I'm not sure if this is related, but the red/green contrast here is very suboptimal. Its not a real problem - I can just mark the code snipped, but a improvement would be nice for newcomers with color blindness I think.

[toddjordan]

ok, this is happening @jenweber! 🔥 The PR is ready. just needs some changes I made to get it building with the current level of code, and for one of us to update the tutorial guides source

[toddjordan]

@luxferresum I think what you mention is more an issue with the guides than this tutorial example. I encourage you to write an issue to https://github.com/ember-learn/guides-source

[toddjordan]

I created an issue for adding the a11y updates here to guides: ember-learn/guides-source#778