[BUG] Inconsistent comment in EnumTest.java

[panthap2]

#6130 ### Description

This comment is inconsistent:

openapi-generator/samples/server/petstore/jaxrs-cxf/src/gen/java/org/openapitools/model/EnumTest.java

Line 228 in e2e3405

* @return enumNumber

Suggest a fix

The method returns the value of enumNumber, rather than enumNumber itself. And if it is not set, it will return null.