Run rustfmt

Run cargo fmt --all and report all formatting differences in a nice overview. It works best in combination with actions-rust-lang/setup-rust-toolchain for problem matcher highlighting.

Execution Summary:

Problem Matcher:

Example workflow

name: "Test Suite"
on:
  push:
  pull_request:

jobs:
  formatting:
    name: cargo fmt
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      # Ensure rustfmt is installed and setup problem matcher
      - uses: actions-rust-lang/setup-rust-toolchain@v1
        with:
          components: rustfmt
      - name: Rustfmt Check
        uses: actions-rust-lang/rustfmt@v1