Adjusted _resolveAliases to allow for object aliases

[micahgodbolt]

When resolving aliases I added a check to see if alias value was a string, otherwise it uses the value key, mimicking the props data structure.

We want to do this because some sets of aliases need additional meta data that we'll be using to check a11y.

Something like:

aliases:
  foreground:
    value: white
    contrastsTo: background
  background:
    value: black

This also allows for better meta data when documenting all of your aliases.

[kaelig]

Thanks @micahgodbolt, do you need some help to write some tests around this feature?

[micahgodbolt]

I'm going to try to tackle the testing updates on this. Wish me luck!

[kaelig]

[jina]

[kaelig]

This PR contains a commit that was merged as part of #69 / #66, but you're still on the spot for writing tests for it and mention the change in the release notes :)