[Not ready to merge] Migrating AttrName, ClassName, and PropName to web-dom.

[nsaunders]

Prerequisites

• Before opening a pull request, please check the HTML standard (https://html.spec.whatwg.org/). If it doesn't appear in this spec, it may be present in the spec for one of the other purescript-web projects. Although MDN is a great resource, it is not a suitable reference for this project.

Description of the change

With this change, the AttrName, ClassName, and PropName types are re-exported from web-dom, completing the migration discussed in purescript-web/purescript-web-dom#56 and purescript-web/purescript-web-dom#58.

Warning
As this change depends on purescript-web/purescript-web-dom#58 which is not yet merged, the purescript-web-dom reference in bower.json points to my personal fork. This will of course need to be updated before this PR can be merged.

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Checklist:

• Added the change to the changelog's "Unreleased" section with a reference to this PR (e.g. "- Made a change (#0000)")
• Linked any existing issues or proposals that this pull request should close
• Updated or added relevant documentation N/A
• Added a test for the contribution (if applicable) N/A

[flip111]

@nsaunders i guess this can be merged now since it is in web-dom?