Add explicit tag nesting rules for <picture> and <button> elements

[tzdesign]

Description

This PR introduces dedicated tag nesting rules for <picture> and <button> elements to improve HTML validation in the Qwik server-side renderer.

Changes

• Added new TagNesting.PICTURE and TagNesting.BUTTON constants.
• Updated allowedContent() to describe valid children for <picture> (<source>, <img>) and <button> (phrasing content except interactive elements).
• Implemented isInPicture() to restrict <picture> children to valid HTML elements.
• Implemented isInButton() to disallow nested interactive elements inside <button>.
• Adjusted isInPhrasing() to route <picture> and <button> appropriately.
• Updated bitmask values for existing table-related constants to accommodate new entries.

Why

Previously, <picture> and <button> elements were validated only under generic phrasing content rules. This allowed invalid nesting (e.g., interactive elements inside <button> or unrelated tags inside <picture>). By adding explicit states and validation logic, HTML output from Qwik will better comply with the HTML specification and prevent common markup mistakes.

Benefits

• Stricter HTML validation for server-rendered output.
• Prevention of invalid interactive nesting inside <button>.
• Proper enforcement of <picture> allowed children.

Checklist

• My code follows the developer guidelines of this project
• I performed a self-review of my own code as well of GPT5 ;)
• I added a changeset with pnpm change

[changeset-bot]

🦋 Changeset detected

Latest commit: 321b52d

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

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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[pkg-pr-new]

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commit: 321b52d

[wmertens]

[gioboa]

Suggested change

	Add explicit tag nesting rules for <picture> and <button> elements
	FIX: add explicit tag nesting rules for <picture> and <button> elements

[gioboa]

Thanks @tzdesign for your PR, I have one small feedback

[tzdesign]

@wmertens you over ruled @gioboa ?

@gioboa maybe another pr, but I will make sure to keep the structure. We are started with changesets ourselves last week.

[wmertens]

oops the merge ignored the unresolved conversation because on the v2 branch it's not needed :(