Implement short set in accordance with RFC

See https://wiki.php.net/rfc/property-hooks#short-set, changed from original

src/main/php/lang/ast/emit/PropertyHooks.class.php

@@ -142,7 +142,7 @@ protected function emitProperty($result, $property) {
           $method,
           new Signature($hook->parameter ? [$hook->parameter] : [new Parameter('value', null)], null),
           null === $hook->expression ? null : [$this->rewriteHook(
-            $hook->expression,
+            $hook->expression instanceof Block ? $hook->expression : new Assignment($virtual, '=', $hook->expression),
             $property->name,
             $virtual,
             $literal

src/test/php/lang/ast/unittest/emit/PropertyHooksTest.class.php

@@ -55,7 +55,7 @@ public function run() {
   #[Test]
   public function set_expression() {
     $r= $this->run('class %T {
-      public $test { set => $this->test= ucfirst($value); }
+      public $test { set => ucfirst($value); }
 
       public function run() {
         $this->test= "test";
@@ -96,7 +96,7 @@ public function get_and_set_using_property() {
     $r= $this->run('class %T {
       public $test {
         get => $this->test;
-        set => $this->test= ucfirst($value);
+        set => ucfirst($value);
       }
 
       public function run() {
@@ -128,7 +128,7 @@ public function run() {
   public function typed_set() {
     $r= $this->run('use util\\Bytes; class %T {
       public string $test {
-        set(string|Bytes $arg) => $this->test= ucfirst($arg);
+        set(string|Bytes $arg) => ucfirst($arg);
       }
 
       public function run() {
@@ -144,7 +144,7 @@ public function run() {
   public function typed_mismatch() {
     $this->run('class %T {
       public string $test {
-        set(int $times) => $this->test= $times." times";
+        set(int $times) => $times." times";
       }
 
       public function run() {
@@ -203,7 +203,7 @@ public function reflection() {
     $t= $this->declare('class %T {
       public string $test {
         get => $this->test;
-        set => $this->test= ucfirst($value);
+        set => ucfirst($value);
       }
     }');