docs: improve closure variable inheritance examples

language/functions.xml

@@ -1173,64 +1173,68 @@ $greet('PHP');
     <programlisting role="php">
 <![CDATA[
 <?php
+// A variable defined in the parent scope
 $message = 'hello';
 
-// No "use"
+// $message is not inherited and is undefined due to the
+// lack of a "use" clause 
 $example = function () {
-    var_dump($message);
+    var_dump($message); // undefined
 };
-$example();
+$example(); // NULL
 
-// Inherit $message
+// $message is inherited from the parent scope due to the 
+// "use" clause
 $example = function () use ($message) {
     var_dump($message);
 };
-$example();
+$example(); // "hello"
 
 // Inherited variable's value is from when the function
-// is defined, not when called
+// was defined, not when called
 $message = 'world';
-$example();
-
-// Reset message
+$example(); // "hello"
+// Reset $message
 $message = 'hello';
 
-// Inherit by-reference
+// A changed value in the parent scope will be reflected 
+// when called if $message is passed by reference
 $example = function () use (&$message) {
     var_dump($message);
 };
-$example();
-
-// The changed value in the parent scope
-// is reflected inside the function call
 $message = 'world';
-$example();
+$example(); // "world" instead of "hello"
 
-// Closures can also accept regular arguments
+// Closures can accept regular arguments
 $example = function ($arg) use ($message) {
     var_dump($arg . ' ' . $message);
 };
-$example("hello");
+$example("hello"); // "hello world"
 
-// Return type declaration comes after the use clause
-$example = function () use ($message): string {
-    return "hello $message";
+// Closures can return values like other function types
+// and return type declaration comes after the "use"
+$example = function () use ($message): array {
+    return ["hello", $message];
 };
-var_dump($example());
+var_dump($example()); // array("hello", "world")
 ?>
 ]]>
     </programlisting>
     &example.outputs.similar;
     <screen>
 <![CDATA[
-Notice: Undefined variable: message in /example.php on line 6
+Warning: Undefined variable $message in /example.php on line 8
 NULL
 string(5) "hello"
 string(5) "hello"
-string(5) "hello"
 string(5) "world"
 string(11) "hello world"
-string(11) "hello world"
+array(2) {
+  [0]=>
+  string(5) "hello"
+  [1]=>
+  string(5) "world"
+}
 ]]>
     </screen>
    </example>