Add enum to Java docs

* Parameter enum values
* Inner enum class (model property)
* Outer enum class (enum model/definition)

samples/client/petstore/java/okhttp-gson/docs/Dog.md

@@ -0,0 +1,11 @@
+
+# Dog
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**className** | **String** |  | 
+**breed** | **String** |  |  [optional]
+
+
+