[ENH] improve error message when folder to index does not exist #110

	---
	name: validate

	on:
	push:
	branches: ['*']
	pull_request:
	branches: ['*']

	jobs:

	validate_cff:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- name: Check whether the citation metadata from CITATION.cff is valid
	uses: citation-file-format/cffconvert-github-action@2.0.0
	with:
	args: --validate

	codespell:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- uses: codespell-project/actions-codespell@master

	markdown_link_check:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- uses: gaurav-nelson/github-action-markdown-link-check@v1
	with:
	use-quiet-mode: yes
	use-verbose-mode: yes
	config-file: .github/workflows/mlc_config.json

	miss_hit:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	command: [mh_style, mh_metric --ci, mh_lint]
	fail-fast: false
	steps:
	- uses: actions/checkout@v3
	with:
	submodules: true
	fetch-depth: 1
	- name: Set up Python
	uses: actions/setup-python@v2
	with:
	python-version: 3.11
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip setuptools
	pip3 install -r requirements.txt
	- name: ${{ matrix.command }}
	run: \|
	${{ matrix.command }}

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