Support using class references in form of strings for package()

Author: thekid

src/main/php/lang/Reflection.class.php

@@ -78,6 +78,8 @@ public static function package($arg) {
       $name= strtr($arg, '\\', '.');
       if ($cl->providesPackage($name)) {
         return new Package($name);
+      } else if ($cl->providesClass($name)) {
+        return new Package(substr($name, 0, strrpos($name, '.')));
       }
       throw new IllegalArgumentException('No package named '.$name);
     }

src/test/php/lang/reflection/unittest/ReflectionTest.class.php

@@ -23,6 +23,8 @@ private function arguments() {
   private function packages() {
     yield [__NAMESPACE__, 'namespace literal'];
     yield ['lang.reflection.unittest', 'namespace name'];
+    yield [self::class, 'class literal'];
+    yield [nameof($this), 'class name'];
     yield [$this, 'instance'];
     yield [Type::forName(self::class), 'type'];
     yield [Reflection::of(self::class), 'reflection'];