Composer: add script descriptions

... as it is now less intuitive to run the unit tests via the Composer scripts, so improve the discoverability of the different scripts by adding descriptions for each script.

composer.json

@@ -93,5 +93,14 @@
     "coverage10": [
       "@php ./vendor/phpunit/phpunit/phpunit -c phpunit10.xml.dist"
     ]
+  },
+  "scripts-descriptions": {
+    "lint": "Lint PHP files to find parse errors.",
+    "checkcs": "Check the entire codebase for code-style issues.",
+    "fixcs": "Fix all auto-fixable code-style issues in the entire codebase.",
+    "test": "Run the unit tests on PHPUnit 5.x - 9.x without code coverage.",
+    "test10": "Run the unit tests on PHPUnit 10.x without code coverage.",
+    "coverage": "Run the unit tests on PHPUnit 5.x - 9.x with code coverage.",
+    "coverage10": "Run the unit tests on PHPUnit 10.x with code coverage."
   }
 }