Fold `util` module into `bash` and `fish` #102

	name: shell-quote CI

	on:
	push:
	schedule:
	- cron: "0 0 * * 0" # weekly

	jobs:
	test:
	name: Test
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: dtolnay/rust-toolchain@stable
	# Make sure we have all the target shells installed.
	- run: sudo apt-get install -y bash dash fish zsh
	# Record shell versions. Almost unbelievably, it's not possible to get the
	# version of Dash from `dash` itself, so we skip it here. Since `sh` might
	# be `dash`, we also do not try to get its version.
	- name: Shell versions
	run: \|
	for shell in sh dash; do
	for path in $(type -ap "$shell"); do
	printf "%10s @ %-30q\n" "$shell" "$path"
	done
	done
	for shell in bash fish zsh; do
	for path in $(type -ap "$shell"); do
	read -r version < <($path --version)
	printf "%10s @ %-30q: %s\n" "$shell" "$path" "$version"
	done
	done
	# Test in debug mode first.
	- run: cargo test
	# Test in release mode too, to defend against, for example, use of
	# `debug_assert!` with side effects, i.e. those side effects won't happen
	# when compiled with `--release`.
	- run: cargo test --release

	fmt:
	name: Rustfmt
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: dtolnay/rust-toolchain@stable
	with:
	components: rustfmt
	- run: cargo fmt --all -- --check

	clippy:
	name: Clippy # i.e. `cargo check` plus extra linting.
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: dtolnay/rust-toolchain@stable
	with:
	components: clippy
	- run: cargo clippy --all-targets -- -D warnings

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