Docs for the "java" plugin appear to just be docs for "java-resolvers"

**Describe the bug**

The docs at appear to be mostly a copy and paste of a portion of the docs from .

The **Installation** section tell you to install `@graphql-codegen/java`, but then all of the usage examples are using the plugin `java-resolvers`.

**To Reproduce**

Visit the links above? 😊

**Expected behavior**

I'd expect the **Java** section to describe the operation & usage of the [java plugin](https://github.com/dotansimha/graphql-code-generator/tree/master/packages/plugins/java/java).

**Environment:**

Chrome! 😜