fix: role for th element in context

[jlp-craigmorten]

Changes

Relates to #25

Updates the role returned for a th element to be either:

1. columnheader when the scope is col or colgroup;
2. rowheader when the scope is row or rowgroup;
3. gridcell when the element is nested within a table element with role grid or treegrid;
4. cell when the element is nested within a table element otherwise;
5. columnheader otherwise per the existing precedent to return a sensible defaults unless empty ancestors are explicitly provided.

This detail is currently missing from the HTML-ARIA spec, but is describe in the sibling HTML-AAM spec:

• https://www.w3.org/TR/html-aam-1.0/#el-th - missing scope and nested within a table
• https://www.w3.org/TR/html-aam-1.0/#el-th-gridcell - missing scope and nested within a grid or treegrid
• https://www.w3.org/TR/html-aam-1.0/#el-th-columnheader - column like scopes
• https://www.w3.org/TR/html-aam-1.0/#el-th-rowheader - row like scopes

How to Review

Nothing of note.

Checklist

• Unit tests updated

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🦋 Changeset detected

Latest commit: 5c450df

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

This PR includes changesets to release 1 package

Name	Type
html-aria	Patch

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