Fix lint errors

mtproto/rpc/handshake_request.go

@@ -2,9 +2,12 @@ package rpc
 
 import "bytes"
 
+// HandshakeRequest is the data type which is responsible for
+// constructing of correct handshake request.
 type HandshakeRequest struct {
 }
 
+// Bytes returns serialized handshake request.
 func (r *HandshakeRequest) Bytes() []byte {
 	buf := &bytes.Buffer{}
 	buf.Grow(len(TagHandshake) + len(HandshakeFlags) + len(HandshakeSenderPID) + len(HandshakePeerPID))
@@ -17,6 +20,7 @@ func (r *HandshakeRequest) Bytes() []byte {
 	return buf.Bytes()
 }
 
+// NewHandshakeRequest creates new HandshakeRequest instance.
 func NewHandshakeRequest() *HandshakeRequest {
 	return &HandshakeRequest{}
 }