Add description `Predef.identity` method.
Add description `Predef.identity` method.

martijnhoekstra/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,lrytz/scala,lrytz/scala,martijnhoekstra/scala,scala/scala,martijnhoekstra/scala,scala/scala,lrytz/scala,scala/scala,martijnhoekstra/scala,lrytz/scala,lrytz/scala,scala/scala,martijnhoekstra/scala,scala/scala