Mention $CI in documentation section "Influential environment variabl… #15

	name: Deploy documentation

	on:
	push:
	branches: ['master']
	paths: ['doc/**']

	jobs:
	build_html:
	runs-on: ${{matrix.os}}

	strategy:
	matrix:
	os: [ubuntu-latest]
	emacs_version: ['29.1']

	steps:
	# We want to call it via Eldev, to reuse command line etc. Certainly an overkill, but
	# hardly important, our regression testing action is magnitudes more costly anyway.
	- name: Set up Emacs
	uses: jcs090218/setup-emacs@master
	with:
	version: ${{matrix.emacs_version}}

	- name: Set up Asciidoctor
	run: sudo apt-get -y install asciidoctor

	- name: Check out the source code
	uses: actions/checkout@v4

	- name: Build documentation HTML
	run: \|
	./bin/eldev -dtTC documentation
	env:
	ELDEV_LOCAL: "."

	- name: Deploy resulting HTML to GitHub Pages
	uses: peaceiris/actions-gh-pages@v3
	with:
	deploy_key: ${{secrets.ACTIONS_DEPLOY_KEY}}
	publish_branch: github-pages
	publish_dir: ./htmldoc

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