Improve docs for `String#rindex!` #4288

	name: LLVM CI

	on: [push, pull_request]

	permissions: {}

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}

	env:
	SPEC_SPLIT_DOTS: 160

	jobs:
	llvm_test:
	runs-on: ${{ matrix.runs-on }}
	strategy:
	fail-fast: false
	matrix:
	include:
	- {llvm_version: 13, runs-on: ubuntu-22.04, codename: jammy}
	- {llvm_version: 14, runs-on: ubuntu-22.04, codename: jammy}
	- {llvm_version: 15, runs-on: ubuntu-22.04, codename: jammy}
	- {llvm_version: 16, runs-on: ubuntu-22.04, codename: jammy}
	- {llvm_version: 17, runs-on: ubuntu-24.04, codename: noble}
	- {llvm_version: 18, runs-on: ubuntu-24.04, codename: noble}
	- {llvm_version: 19, runs-on: ubuntu-24.04, codename: noble}
	name: "LLVM ${{ matrix.llvm_version }}"
	steps:
	- name: Checkout Crystal source
	uses: actions/checkout@v4

	- name: Install LLVM ${{ matrix.llvm_version }}
	run: \|
	sudo apt remove 'llvm-' 'libllvm'
	wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key \| sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
	sudo apt-add-repository -y deb http://apt.llvm.org/${{ matrix.codename }}/ llvm-toolchain-${{ matrix.codename }}-${{ matrix.llvm_version }} main
	sudo apt install -y llvm-${{ matrix.llvm_version }}-dev lld

	- name: Install Crystal
	uses: crystal-lang/install-crystal@v1
	with:
	crystal: "1.14.0"

	- name: Build libllvm_ext
	run: make -B deps

	- name: Test compiler_spec
	run: make compiler_spec junit_output=.junit/compiler_spec.xml

	- name: Integration test
	run: make crystal std_spec threads=1 junit_output=.junit/std_spec.xml

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