Verify formatting of code snippets in CI

Author: alexandear

Diff for: .ci.readme.fmt.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# Verify that the code snippets in README.md are formatted.
+# The tool https://github.com/hougesen/mdsf is used.
+
+if [ -n "$(mdsf verify --config .mdsf.json README.md 2>&1)" ]; then
+  echo "Go code in the README.md is not formatted."
+  echo "Did you forget to run 'mdsf format --config .mdsf.json README.md'?"
+  exit 1
+fi

Diff for: .github/workflows/main.yml

@@ -15,6 +15,7 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version: ${{ matrix.go_version }}
+      - uses: actions/setup-node@v4
       - run: ./.ci.gogenerate.sh
       - run: ./.ci.gofmt.sh
       - run: ./.ci.govet.sh
@@ -37,3 +38,15 @@ jobs:
         with:
           go-version: ${{ matrix.go_version }}
       - run: go test -v -race ./...
+  format:
+    name: Check formatting of code snippets in markdown files
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: stable
+      - run: npm install -g mdsf-cli
+      - run: ./.ci.gofmt.sh
+      - run: ./.ci.readme.fmt.sh

Diff for: .mdsf.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "https://raw.githubusercontent.com/hougesen/mdsf/main/schemas/v0.4.1/mdsf.schema.json",
+  "format_finished_document": false,
+  "languages": {
+    "go": [
+      [
+        "gofmt",
+        "goimports"
+      ]
+    ]
+  }
+}