resolver/manual: fix minor typo (#1960)
resolver/manual: fix minor typo (#1960)

Signed-off-by: Gyuho Lee <3454051ee3341eb69bdf6fca40899cdad4d86496@gmail.com>
improbable-io/grpc-go,MakMukhi/grpc-go,grpc/grpc-go,MakMukhi/grpc-go,dfawley/grpc-go,thinkerou/grpc-go,stanley-cheung/grpc-go,stanley-cheung/grpc-go,improbable-io/grpc-go,menghanl/grpc-go,menghanl/grpc-go,dfawley/grpc-go,grpc/grpc-go,thinkerou/grpc-go