update docs to match change to any

Author: dariuszkuc

docs/client/client-customization.md

@@ -150,13 +150,13 @@ val customObjectMapper = jacksonObjectMapper()
 val client = GraphQLClient(url = URL("http://localhost:8080/graphql"), mapper = customObjectMapper)
 ```
 
-## Deprecated Field Usage
+## Deprecated Field Usage
 
 Build plugins will automatically fail generation of a client if any of the specified query files are referencing
 deprecated fields. This ensures that your clients have to explicitly opt-in into deprecated usage by specifying
 `allowDeprecatedFields` configuration option.
 
-## Custom GraphQL Scalars
+## Custom GraphQL Scalars
 
 By default, custom GraphQL scalars are serialized and [type-aliased](https://kotlinlang.org/docs/reference/type-aliases.html)
 to a String. GraphQL Kotlin plugins also support custom serialization based on provided configuration.
@@ -171,8 +171,8 @@ import com.expediagroup.graphql.client.converter.ScalarConverter
 import java.util.UUID
 
 class UUIDScalarConverter : ScalarConverter<UUID> {
-    override fun toScalar(rawValue: String): UUID = UUID.fromString(rawValue)
-    override fun toJson(value: UUID): String = value.toString()
+    override fun toScalar(rawValue: Any): UUID = UUID.fromString(rawValue.toString())
+    override fun toJson(value: UUID): Any = value.toString()
 }
 ```
 
@@ -189,6 +189,4 @@ graphql {
 }
 ```
 
-See [Gradle](../plugins/gradle-plugin.md)
-and [Maven](../plugins/maven-plugin.md)
-plugin documentation for additional details.
+See [Gradle](../plugins/gradle-plugin.md) and [Maven](../plugins/maven-plugin.md) plugin documentation for additional details.

plugins/graphql-kotlin-plugin-core/src/test/kotlin/com/expediagroup/graphql/plugin/generator/types/GenerateGraphQLCustomScalarTypeSpecIT.kt

@@ -36,6 +36,7 @@ class GenerateGraphQLCustomScalarTypeSpecIT {
                 import com.fasterxml.jackson.annotation.JsonCreator
                 import com.fasterxml.jackson.annotation.JsonValue
                 import kotlin.Any
+                import kotlin.String
                 import kotlin.jvm.JvmStatic
 
                 const val CUSTOM_SCALAR_TEST_QUERY: String =