[docs] fix gradle plugin tasks example (#1406)

Author: Dariusz Kuc

website/docs/plugins/gradle-plugin-tasks.mdx

@@ -208,10 +208,10 @@ on those tasks or explicitly creating them). **Configuring plugin through the `g
 all the corresponding tasks**.
 
 All `graphql-kotlin-gradle-plugin` tasks are grouped together under `GraphQL` task group and their names are prefixed with
-`graphql`. You can find detailed information about GraphQL kotlin tasks by running Gradle `help --task <taskName>` task.
+`graphql`. You can find detailed information about GraphQL kotlin tasks by running `gradle help --task <taskName>`.
 
 ```shell
-$ gradle --tasks
+$ gradle tasks --group graphql
 
 GraphQL tasks
 -------------