feat(.github/workflows/general.yml): improving file a bit (mostly adding comments) (#202)

.github/workflows/general.yml

@@ -1,5 +1,7 @@
+# The name of your workflow. GitHub displays the names of your workflows on your repository's "Actions" tab
 name: Rust
 
+# To automatically trigger the workflow
 on:
   # NB: this differs from the book's project!
   # These settings allow us to run this specific CI pipeline for PRs against
@@ -15,17 +17,35 @@ on:
 env:
   CARGO_TERM_COLOR: always
 
+# A workflow run is made up of one or more jobs, which run in parallel by default
+# Each job runs in a runner environment specified by runs-on
 jobs:
+# Unique identifier of our job (`job_id`)
   test:
+    # Sets the name `Test` for the job, which is displayed in the GitHub UI
     name: Test
+    # Containers must run in Linux based operating systems
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@stable
-      - uses: Swatinem/rust-cache@v2
+        # Downloads a copy of the code in your repository before running CI tests
+      - name: Check out repository code
+        # The uses keyword specifies that this step will run v3 of the actions/checkout action. 
+        # This is an action that checks out your repository onto the runner, allowing you to run scripts or other actions against your code (such as build and test tools). 
+        # You should use the checkout action any time your workflow will run against the repository's code.
+        uses: actions/checkout@v3
+
+      # This GitHub Action installs a Rust toolchain using rustup. It is designed for one-line concise usage and good defaults.
+      - name: Install the Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      # A GitHub Action that implements smart caching for rust/cargo projects with sensible defaults.
+      - name: Rust Cache Action
+        uses: Swatinem/rust-cache@v2
+
       - name: Run tests
         run: cargo test
 
+  # `fmt` container job
   fmt:
     name: Rustfmt
     runs-on: ubuntu-latest
@@ -33,6 +53,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@stable
         with:
+          # Specific to dtolnay/rust-toolchain: Comma-separated string of additional components to install
           components: rustfmt
       - name: Enforce formatting
         run: cargo fmt --check
@@ -49,6 +70,7 @@ jobs:
       - name: Linting
         run: cargo clippy -- -D warnings
 
+  # `coverage` container job
   coverage:
     name: Code coverage
     runs-on: ubuntu-latest