feat: parsing the rpc's trailing comment followed by the left curly brace

[yoheimuta]

ref. https://github.com/yoheimuta/protolint/issues/292#issuecomment-1305356269

The parser is supposed to extract // get the global address table from the below snippet.

service SearchService {
  rpc GetAll(GetRequest) returns(GetReply) { // get the global address table
    option(requestreply.Nats).Subject = "get.addrs";
  }
}