HTML API: Add support for the rest of the common IN BODY tags.

[dmsnell]

TODO

• Run the html5lib tests against these updated elements
• Generate unit tests to cover these updated elements
• Handle closing tags for the special elements? These might be covered already by the "any other end tag" section.

Description

Adds support for the rest of the "easy" and common tags to support within the IN BODY insertion mode. The goal of this patch is to unlock as many posts for full support as possible without requiring that we add too much additional complexity into the HTML Processor. In other words: what can we support in 6.5 without putting too much pressure on review and testing?

Adds support for the following elements:

• APPLET
• IFRAME
• MARQUEE
• NOEMBED
• OBJECT
• TEXTAREA
• WBR
• XMP

[github-actions]

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[sirreal]

I think this has been superseded, can we close the PR?

[dmsnell]

Yes, thank you @sirreal