Improved spring-cloud-wiremock documentation (#780)
Improved spring-cloud-wiremock documentation (#780)

Sometimes people want to use methods like `addMockServiceRequestListener`, which are not static. But there is no any notes about  `WireMockServer` in spring-cloud-wiremock documentation. 

I saw how the developers did not know about it and made a mistake. 
They mixed junit4 and junit5 even for new services, because `WireMockRule` inherits from `WireMockServer` and  provides non static methods.

This situation may seem funny, but many can get into it.
spring-cloud/spring-cloud-contract,spring-cloud/spring-cloud-contract,spring-cloud/spring-cloud-contract