feat: GitHub-style markdown alerts as callouts

.github/workflows/build-assets.yml

@@ -11,20 +11,13 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setting up node ${{ matrix.node-version }}
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-      - name: Cache npm modules
-        uses: actions/cache@v2
-        with:
-          # npm cache files are stored in `~/.npm` on Linux/macOS
-          path: ~/.npm
-          key: ${{ runner.OS }}-node-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.OS }}-node-
-            ${{ runner.OS }}-
+          cache: npm
+          cache-dependency-path: public/template/package-lock.json
       - run: npm ci
         working-directory: ./public/template
       - run: npm run release

.github/workflows/validate.yml

@@ -6,7 +6,7 @@ jobs:
   validate-json:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Validate language file
         uses: docker://orrosenblatt/validate-json-action:latest
         env:

.gitignore

@@ -11,3 +11,4 @@ node_modules/
 sources.json
 markdown/
 public/template/package-lock.json
+.phpunit.result.cache

README.md

@@ -124,6 +124,31 @@ For the language switch to work, you also need to index the translations with `p
 
 **These index actions are done automatically for changed files only (much faster!) as part of `php docs.php sources:update`.** Typically you'd only need to run the full indexing the first time setting up a mirror or clone.
 
+## Markdown alerts
+
+GitHub-style alert blockquotes render as the existing `.c-callout` boxes:
+
+```markdown
+> [!NOTE]
+> Extra detail for the reader.
+
+> [!TIP]
+> A shortcut or recommended approach.
+
+> [!IMPORTANT]
+> Something easy to miss.
+
+> [!WARNING]
+> Risk or breaking change.
+
+> [!CAUTION]
+> Stronger warning than WARNING.
+```
+
+Spaces inside the marker (`[! NOTE]`) are accepted. Tables and other CommonMark features are unchanged.
+
+Page-level git history (last change and contributors) is already shown on documentation pages from the search/history index. A separate site-wide docs changelog UI is not part of this feature.
+
 ## Building assets
 
 From the `public/template/` directory, first load the dependencies with `npm install`.

composer.json

@@ -30,7 +30,8 @@
         "voku/stop-words": "^2.0"
     },
     "require-dev": {
-        "ext-intl": "*"
+        "ext-intl": "*",
+        "phpunit/phpunit": "^9.6"
     },
     "autoload": {
         "psr-4": {