chore: update samples

Author: takkiraz

samples/client/petstore/kotlin-nullable/docs/PetApi.md

@@ -108,7 +108,7 @@ Configure petstore_auth:
 
 <a id="findPetsByStatus"></a>
 # **findPetsByStatus**
-> kotlin.collections.List&lt;Pet&gt; findPetsByStatus(status)
+> kotlin.collections.List&lt;Pet&gt;? findPetsByStatus(status)
 
 Finds Pets by status
 
@@ -141,7 +141,7 @@ try {
 
 ### Return type
 
-[**kotlin.collections.List&lt;Pet&gt;**](Pet.md)
+[**kotlin.collections.List&lt;Pet&gt;?**](Pet.md)
 
 ### Authorization
 
@@ -156,7 +156,7 @@ Configure petstore_auth:
 
 <a id="findPetsByTags"></a>
 # **findPetsByTags**
-> kotlin.collections.List&lt;Pet&gt; findPetsByTags(tags)
+> kotlin.collections.List&lt;Pet&gt;? findPetsByTags(tags)
 
 Finds Pets by tags
 
@@ -189,7 +189,7 @@ try {
 
 ### Return type
 
-[**kotlin.collections.List&lt;Pet&gt;**](Pet.md)
+[**kotlin.collections.List&lt;Pet&gt;?**](Pet.md)
 
 ### Authorization
 
@@ -204,7 +204,7 @@ Configure petstore_auth:
 
 <a id="getPetById"></a>
 # **getPetById**
-> Pet getPetById(petId)
+> Pet? getPetById(petId)
 
 Find pet by ID
 
@@ -237,7 +237,7 @@ try {
 
 ### Return type
 
-[**Pet**](Pet.md)
+[**Pet?**](Pet.md)
 
 ### Authorization
 
@@ -347,7 +347,7 @@ Configure petstore_auth:
 
 <a id="uploadFile"></a>
 # **uploadFile**
-> ModelApiResponse uploadFile(petId, additionalMetadata, file)
+> ModelApiResponse? uploadFile(petId, additionalMetadata, file)
 
 uploads an image
 
@@ -382,7 +382,7 @@ try {
 
 ### Return type
 
-[**ModelApiResponse**](ModelApiResponse.md)
+[**ModelApiResponse?**](ModelApiResponse.md)
 
 ### Authorization
 

samples/client/petstore/kotlin-nullable/docs/StoreApi.md

@@ -57,7 +57,7 @@ No authorization required
 
 <a id="getInventory"></a>
 # **getInventory**
-> kotlin.collections.Map&lt;kotlin.String, kotlin.Int&gt; getInventory()
+> kotlin.collections.Map&lt;kotlin.String, kotlin.Int&gt;? getInventory()
 
 Returns pet inventories by status
 
@@ -87,7 +87,7 @@ This endpoint does not need any parameter.
 
 ### Return type
 
-**kotlin.collections.Map&lt;kotlin.String, kotlin.Int&gt;**
+**kotlin.collections.Map&lt;kotlin.String, kotlin.Int&gt;?**
 
 ### Authorization
 
@@ -103,7 +103,7 @@ Configure api_key:
 
 <a id="getOrderById"></a>
 # **getOrderById**
-> Order getOrderById(orderId)
+> Order? getOrderById(orderId)
 
 Find purchase order by ID
 
@@ -136,7 +136,7 @@ try {
 
 ### Return type
 
-[**Order**](Order.md)
+[**Order?**](Order.md)
 
 ### Authorization
 
@@ -149,7 +149,7 @@ No authorization required
 
 <a id="placeOrder"></a>
 # **placeOrder**
-> Order placeOrder(body)
+> Order? placeOrder(body)
 
 Place an order for a pet
 
@@ -180,7 +180,7 @@ try {
 
 ### Return type
 
-[**Order**](Order.md)
+[**Order?**](Order.md)
 
 ### Authorization
 

samples/client/petstore/kotlin-nullable/docs/UserApi.md

@@ -192,7 +192,7 @@ No authorization required
 
 <a id="getUserByName"></a>
 # **getUserByName**
-> User getUserByName(username)
+> User? getUserByName(username)
 
 Get user by user name
 
@@ -223,7 +223,7 @@ try {
 
 ### Return type
 
-[**User**](User.md)
+[**User?**](User.md)
 
 ### Authorization
 
@@ -236,7 +236,7 @@ No authorization required
 
 <a id="loginUser"></a>
 # **loginUser**
-> kotlin.String loginUser(username, password)
+> kotlin.String? loginUser(username, password)
 
 Logs user into the system
 
@@ -269,7 +269,7 @@ try {
 
 ### Return type
 
-**kotlin.String**
+**kotlin.String?**
 
 ### Authorization