Add note for libxml handlers in UPGRADING.INTERNALS #1

	name: Docs
	on:
	push:
	branches:
	- master
	paths:
	- docs/**
	pull_request:
	paths:
	- docs/**
	jobs:
	pages:
	runs-on: ubuntu-22.04
	permissions:
	pages: write
	id-token: write
	if: github.repository == 'php/php-src'
	steps:
	- name: git checkout
	uses: actions/checkout@v4
	- name: Install dependencies
	run: pip install sphinx-design sphinxawesome-theme rstfmt
	- name: Check formatting
	run: rstfmt --check -w 100 docs/source
	- name: Publish
	if: github.event_name == 'push'
	uses: sphinx-notes/pages@v3
	with:
	checkout: false
	documentation_path: docs/source

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