docs: improve documentation generation instructions (#789)

Closes #788

As mentioned in [PR
#772](#772), contributors
need clearer guidance on when and why to regenerate documentation. This
PR addresses [issue
#788](#788).


1. Add `composer docs` command for easier doc generation
2. Update CONTRIBUTING.md to clearly explain when/why you need to
regenerate and commit

This should help prevent CI failures by making the documentation
requirements more explicit.

Author: Ayoub-Mabrouk

CONTRIBUTING.md

@@ -68,9 +68,17 @@ We use [phpDocumentor](https://www.phpdoc.org/) to generate API documentation.
 **Please make sure your new or modified code is covered by proper PHPDoc comments.**
 Good documentation ensures that contributors and users can easily read and understand how the methods and classes work.
 
-To generate documentation locally, make sure phpDocumentor is installed, then run:
+**Important:** You **must** regenerate and commit the documentation after modifying code in `src/` or merging from `master`. The CI will fail if documentation is out of sync.
 
+To generate documentation locally, run:
+
+```bash
+$ composer docs
 ```
+
+Or manually:
+
+```bash
 $ wget https://github.com/phpDocumentor/phpDocumentor/releases/download/v3.8.1/phpDocumentor.phar
 $ php phpDocumentor.phar run -d src -t docs
 ```

composer.json

@@ -52,6 +52,7 @@
     "md": "phpmd --ignore-violations-on-exit src/constants,src/laravel,src/parser,examples/EchoBot/src,examples/EchoBot/public,examples/KitchenSink/src,examples/KitchenSink/public text phpmd.xml",
     "stan": "phpstan analyse",
     "copyright": "tools/check_copyright.sh",
+    "docs": "bash -c '[ -f phpDocumentor.phar ] || curl -L -o phpDocumentor.phar https://github.com/phpDocumentor/phpDocumentor/releases/download/v3.8.1/phpDocumentor.phar; php phpDocumentor.phar run -d src -t docs'",
     "check": [
       "@test",
       "@cs",