Allow casts with a return type of static or this to reference themselves (#1103)

* Allow casts with a return type of static or this to reference themselves

Supports

```php
/**
     * @param $model
     * @param string $key
     * @param $value
     * @param array $attributes
     * @return static
     */
    public function get($model, string $key, $value, array $attributes)
    {
        return new static($value);
    }
```

or

```php
/**
     * @param $model
     * @param string $key
     * @param $value
     * @param array $attributes
     * @return $this
     */
    public function get($model, string $key, $value, array $attributes)
    {
        return new static($value);
    }
```

* Update CHANGELOG.md

tests/Console/ModelsCommand/LaravelCustomCasts/Models/CustomCast.php

@@ -12,6 +12,10 @@ use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Cas
 use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\CustomCasterWithPrimitiveDocblockReturn;
 use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\CustomCasterWithPrimitiveReturn;
 use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\CustomCasterWithReturnType;
+use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\ExtendedSelfCastingCasterWithStaticDocblockReturn;
+use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\ExtendedSelfCastingCasterWithThisDocblockReturn;
+use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\SelfCastingCasterWithStaticDocblockReturn;
+use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\LaravelCustomCasts\Casts\SelfCastingCasterWithThisDocblockReturn;
 use Illuminate\Database\Eloquent\Model;
 
 class CustomCast extends Model
@@ -25,5 +29,10 @@ class CustomCast extends Model
         'casted_property_with_return_nullable_primitive' => CustomCasterWithNullablePrimitiveReturn::class,
         'casted_property_without_return' => CustomCasterWithoutReturnType::class,
         'casted_property_with_param' => CustomCasterWithParam::class . ':param',
+        'casted_property_with_static_return_docblock' => SelfCastingCasterWithStaticDocblockReturn::class,
+        'casted_property_with_this_return_docblock' => SelfCastingCasterWithThisDocblockReturn::class,
+        'extended_casted_property_with_static_return_docblock' => ExtendedSelfCastingCasterWithStaticDocblockReturn::class,
+        'extended_casted_property_with_this_return_docblock' => ExtendedSelfCastingCasterWithThisDocblockReturn::class,
+        'casted_property_with_static_return_docblock_and_param' => SelfCastingCasterWithStaticDocblockReturn::class .':param',
     ];
 }