Remove and update extensions to reflect new stub file

README.md

@@ -73,9 +73,8 @@ Please see [WooCommerce Stubs](https://github.com/php-stubs/woocommerce-stubs)
 
 - Makes it possible to run PHPStan on WordPress plugins and themes
 - Loads [`php-stubs/wordpress-stubs`](https://github.com/php-stubs/wordpress-stubs) package
-- Provides dynamic return type extensions for many core functions
+- Provides dynamic return type extensions for functions that are not covered in [`php-stubs/wordpress-stubs`](https://github.com/php-stubs/wordpress-stubs)
 - Defines some core constants
-- Handles special functions and classes e.g. `is_wp_error()`
 - Validates the optional docblock that precedes a call to `apply_filters()` and treats the type of its first `@param` as certain
 
 ### Usage of an `apply_filters()` docblock

extension.neon

@@ -1,8 +1,4 @@
 services:
-    -
-        class: SzepeViktor\PHPStan\WordPress\IsWpErrorFunctionTypeSpecifyingExtension
-        tags:
-            - phpstan.typeSpecifier.functionTypeSpecifyingExtension
     -
         class: SzepeViktor\PHPStan\WordPress\WpThemeMagicPropertiesClassReflectionExtension
         tags:
@@ -70,7 +66,6 @@ services:
 rules:
     - SzepeViktor\PHPStan\WordPress\HookCallbackRule
     - SzepeViktor\PHPStan\WordPress\HookDocsRule
-    - SzepeViktor\PHPStan\WordPress\IsWpErrorRule
 parameters:
     bootstrapFiles:
         - ../../php-stubs/wordpress-stubs/wordpress-stubs.php

tests/data/get_post.php

@@ -3,7 +3,9 @@
 declare(strict_types=1);
 
 namespace SzepeViktor\PHPStan\WordPress\Tests;
+use WP_Error;
 
+use function is_wp_error;
 use function PHPStan\Testing\assertType;
 
 /** @var \WP_Post $wpPostType */