Fix more PHP library references

Author: morsssss

api-reference/translate.mdx

@@ -110,7 +110,7 @@ print(result.text)  # "Bonjour, le monde !"
 <Tab title="PHP">
 ```php Example request: text translation (without glossary)
 $authKey = "f63c02c5-f056-..."; // Replace with your key
-$deeplClient = new \DeepL\DeepLClient($authKey);
+$deeplClient = new DeepL\DeepLClient($authKey);
 
 $result = $deeplClient->translateText('Hello, world!', null, 'fr');
 echo $result->text; // Bonjour, le monde!

docs/getting-started/intro.mdx

@@ -145,7 +145,7 @@ New user? Follow these quick steps to get started with the DeepL API.
         use DeepL\Client;
 
         $authKey = "{YOUR_API_KEY}"; // replace with your key
-        $deeplClient = new \DeepL\DeepLClient($authKey);
+        $deeplClient = new DeepL\DeepLClient($authKey);
 
         $result = $deeplClient->translateText('Hello, world!', null, 'de');
         echo $result->text;

docs/getting-started/your-first-api-request.mdx

@@ -107,7 +107,7 @@ We included text translation examples for our [client libraries](/docs/getting-s
     use DeepL\Client;
 
     $authKey = "f63c02c5-f056-..."; // Replace with your key
-    $deeplClient = new \DeepL\DeepLClient($authKey);
+    $deeplClient = new DeepL\DeepLClient($authKey);
 
     $result = $deeplClient->translateText('Hello, world!', null, 'fr');
     echo $result->text; // Bonjour, le monde!