docs(examples): add return multi values example for PHP

- Create foo function that returns array with multiple values
- Implement array destructuring assignment in main function
- Add php_uname call to demonstrate system information output
- Show usage of spread operator for variable assignment

examples/return-multi-values.php

@@ -0,0 +1,15 @@
+<?php
+function foo(): array {
+    $a = 1;
+    $b = 2;
+    $c = 3;
+    return [$a, $b, $c];
+}
+
+function main()
+{
+    var_dump(php_uname());
+    [$a, $b, $c] = foo();
+    var_dump($a, $b, $c);
+}
+