protondrive: improves 2fa and draft error messages (#7280)

backend/protondrive/protondrive.go

@@ -72,6 +72,9 @@ func init() {
 		}, {
 			Name: "2fa",
 			Help: `The 2FA code
+
+The value can also be provided with --protondrive-2fa=000000
+
 The 2FA code of your proton drive account if the account is set up with 
 two-factor authentication`,
 			Required: false,
@@ -111,6 +114,8 @@ When a file upload is cancelled or failed before completion, a draft will be
 created and the subsequent upload of the same file to the same location will be 
 reported as a conflict.
 
+The value can also be set by --protondrive-replace-existing-draft=true
+
 If the option is set to true, the draft will be replaced and then the upload 
 operation will restart. If there are other clients also uploading at the same 
 file location at the same time, the behavior is currently unknown. Need to set