Add generate examples to Creating-Observables.md in Wiki (#6260)
Add generate examples to Creating-Observables.md in Wiki (#6260)

Add documentation and example to the wiki for generate.
ReactiveX/RxJava,reactivex/rxjava,NiteshKant/RxJava,NiteshKant/RxJava,ReactiveX/RxJava,artem-zinnatullin/RxJava,artem-zinnatullin/RxJava,reactivex/rxjava