`service` types are exported but never defined

[jonniediegelman]

Given a proto file:

syntax = "proto3";

service MyService {}

Calling protojl on it generates the following code:

# Autogenerated using ProtoBuf.jl v1.0.16 on 2024-12-31T21:39:23.141
# original file: /Systems/test.proto (proto3 syntax)

module test_pb

import ProtoBuf as PB
using ProtoBuf: OneOf
using ProtoBuf.EnumX: @enumx

export MyService

# TODO: SERVICE
#    MyService
end # module

Since MyService is exported but never defined, it will cause linters that are checking for undefined exports to fail.