Fix `Stack` example #3851

	name: Build
	on: [push, pull_request]
	jobs:
	build:
	runs-on: ubuntu-20.04
	steps:
	- uses: actions/checkout@v4
	- name: Set up Ruby
	uses: ruby/setup-ruby@v1
	with:
	ruby-version: 3.1.6
	bundler-cache: true
	- name: Set up coursier
	uses: coursier/setup-action@v1.3.5
	with:
	jvm: adopt:11
	- name: Run mdoc
	run: \|
	./scripts/run-mdoc.sh
	rm -r /tmp/mdoc-out/
	- name: Jekyll build
	run: bundle exec jekyll build
	- name: HTMLProofer
	run: \|
	# # Checking for docs.scala-lang/blob/main leads to a chicken and egg problem because of the edit links of new pages.
	bundle exec htmlproofer ./_site/\
	--only-4xx\
	--ignore-status-codes "400,401,403,429"\
	--ignore-empty-alt\
	--allow-hash-href\
	--enforce-https=false\
	--ignore-urls '/https://github.com/scala/,/www.oracle.com/'

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