feat: add Chapter 5 #35

	name: Check Markdown
	on:
	pull_request

	jobs:
	check-markdown:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout code
	uses: actions/checkout@v4

	- name: Setup Node.js
	uses: actions/setup-node@v4
	with:
	node-version: '21'

	- name: Install mdlint
	run: npm install -g @moonbit/markdown-linter

	- name: Install moonBit
	run: /bin/bash -c "$(curl -fsSL https://cli.moonbitlang.com/install/unix.sh)"

	- name: moon version
	env:
	PATH: /home/runner/.moon/bin:$PATH
	run: moon version --all

	- name: Get changed files
	id: changed-files
	uses: tj-actions/changed-files@v43

	- name: Run mdlint
	env:
	PATH: /home/runner/.moon/bin:$PATH
	ALL_CHANGED_FILES: ${{ steps.changed-files.outputs.all_changed_files }}
	run: \|
	for file in ${ALL_CHANGED_FILES}; do
	if [[ $file == *.md ]]; then
	mdlint $file
	fi
	done

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