Allow any Node, including ShadowRoot, as container

[Peeja]

What:

• Expands the type of container in @emotion/sheet and @emotion/cache to Node.
• Tests the use of a ShadowRoot as a container.

Why:

When using Shadow DOM, stylesheets are scoped to the shadow DOM tree they appear in. The most common place to put them is at the shadow root. But a ShadowRoot, though it contains HTMLElements, is not itself an HTMLElement, though it is a Node. The types only allowed HTMLElements as the container, but as the code is written, any Node should work. The added test validates that.

How:

Broadens a type in a few places and adds one test.

Checklist:

• Documentation
• Tests
• Code complete
• Changeset
  • Note: I've made this a patch bump because it's "just" types. Arguably it could be a minor bump because it's a new feature, according to SemVer. Happy to switch it if you'd prefer.

[changeset-bot]

🦋 Changeset detected

Latest commit: 21d4bd8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@emotion/cache	Patch
@emotion/sheet	Patch

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[srmagura]

Great work 👏. Left two suggestions.

[Peeja]

Thanks! I've committed those suggestions.

[srmagura]

LGTM 🙏. Looks like ESLint is complaining about a trailing space in packages/sheet/src/index.js. Can you run Prettier on that file and push the change? I would push to your branch but I don't have write access to the repo.

@Andarist ready for you to review

[Peeja]

Good catch, @Andarist, thanks! Added.