clippy: use `clone_from()` #222

	name: Deploy Book
	on:
	push:
	branches:
	- main

	jobs:
	deploy:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	with:
	fetch-depth: 0
	- name: Install mdbook
	run: \|
	mkdir mdbook
	curl -Lf https://github.com/rust-lang/mdBook/releases/download/v0.4.25/mdbook-v0.4.25-x86_64-unknown-linux-gnu.tar.gz \| tar -xz --directory=./mdbook
	echo `pwd`/mdbook >> $GITHUB_PATH
	- name: Build docs
	run: \|
	cd book
	mdbook build
	- name: Update gh-pages branch
	# This has no reason to fail, only the commit step fails if there are no
	# changes.
	continue-on-error: true
	run: \|
	cd book
	git worktree add gh-pages gh-pages
	git config user.name "Deploy from CI"
	git config user.email ""
	cd gh-pages
	git rm -rf dev
	mv ../book dev
	git add dev
	git commit -m "Deploy $GITHUB_SHA to gh-pages"
	- name: Deploy changed book
	# only deploy if there were changes
	if: success()
	run: \|
	cd book/gh-pages
	git push --force

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