Problem description

When using proto-loader-gen-types for ts-types generating, the root ProtoGrpcType type is not declared to extends grpc.GrpcObject.
Because of that, when I grpc.loadPackageDefinition(...), I cannot cast it directly to as MyProtoGrpcType and I have to cast it to as unknown first.
Though root ProtoGrpcType is in fact the extension of grpc.GrpcObject -- the only problem is the absence of declaration.

Reproduction steps

import * as grpc from '@grpc/grpc-js';
import * as protoLoader from '@grpc/proto-loader';
import type { ProtoGrpcType as MyProtoGrpcType } from 'proto/my';

const myPackageDefinition = protoLoader.loadSync('my.proto', { includeDirs: [ 'proto' ] });
const myProtoDescriptor = grpc.loadPackageDefinition(myPackageDefinition) as unknown as MyGrpcType;

Environment

• Any OS name, version and architecture
• Any Node version
• Any Node installation method (nvm or others)
• @grpc/proto-loader:0.7.13

Additional context

@murgatroid99 , I strongly appreciate your creature: the proto-loader-gen-types!
It is a very helpful thing! And I even can go on with as unknown cast.
But this duct-tape of as unknown can be removed -- and please let's do it.
I created a PR addressing this problem, it's very simple. Please take a look.