Add some type resolver details to Readme.md (#1867)

Author: DerManoMann

README.md

@@ -44,22 +44,6 @@ For cli usage from anywhere, install swagger-php globally and make sure to place
 composer global require zircote/swagger-php
 ```
 
-### radebatz/type-info-extras
-`swagger-php` version `5.5` introduces a new type resolver used internally to determine the schema type
-of properties (and other elements with a schema).
-
-By default, a custom `LegacyTypeResolver` is used. If you are on PHP 8.2 or higher,
-the `TypeInfoTypeResolver` can be used instead.
-For this the [radebatz/type-info-extras](https://github.com/DerManoMann/type-info-extras) package is required.
-Since it is optional, it needs to be installed manually. It will also add `symfony/type-info` as a dependency:
-
-```shell
-composer require radebatz/type-info-extras
-```
-
-If the library code is detected, `swagger-php` will automatically use it.
-Advantages are re-use of 3rd party code, better stability and compatibility with future PHP versions.
-
 ### doctrine/annotations
 As of version `4.8` the [doctrine annotations](https://www.doctrine-project.org/projects/annotations.html) library **is optional** and **no longer installed by default**.
 
@@ -127,6 +111,15 @@ $openapi = $serializer->deserialize($jsonString, 'OpenApi\Annotations\OpenApi');
 echo $openapi->toJson();
 ```
 
+## The `LegacyTypeResolver`
+
+As of version 6, resolution of types is done using the `TypeInfoTypeResolver` class. It uses the `symfony/type-info`
+library under the hood which improves handling of complext types.
+
+If this is not desired, the `LegacyTypeResolver` can be used to preserve the old behaviour of version 5.
+
+The `LegacyTypeResolver` is deprecated and will be removed in a future release.
+
 ## [Contributing](CONTRIBUTING.md)
 
 ## More on OpenApi & Swagger