message: remove using from collection header
diff: #include <mongocxx/result/replace_one.hpp>
  #include <mongocxx/result/update.hpp>
  #include <mongocxx/write_concern.hpp>
  +#include <mongocxx/pipeline.hpp>
  #include <mongocxx/config/prelude.hpp>
  namespace mongocxx {
  MONGOCXX_INLINE_NAMESPACE_BEGIN
  -using bsoncxx::builder::basic::kvp;
  -using bsoncxx::builder::basic::make_document;
  -using bsoncxx::builder::concatenate;
  -
  class client;
  class database;
  -class pipeline;
  ///
  /// Class representing server side document groupings within a MongoDB database.
  