Make @Module @Documented
Make @Module @Documented

@ProducerModule is already @Documented

RELNOTES=n/a

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=232902222

ze-pequeno/dagger,google/dagger,ze-pequeno/dagger,dushmis/dagger,google/dagger,ze-pequeno/dagger,ze-pequeno/dagger,cgruber/dagger,cgruber/dagger,google/dagger,google/dagger,dushmis/dagger,cgruber/dagger