JDK-81690687 moved a significant percentage of unshared, shareable members to shared classes like Resources and Contents. Notably omitted at that time was any attempt to cleanup table headers, which are passed around as List<String>. They were omitted because of the potential churn caused by replacing List<String> with a better abstraction.

This addresses that omission, introducing TableHeader as a new mid-level worker class to help create headers for HTML tables, as generated by the standard doclet.