Normalize signature of encodeCommand

[Cellivar]

Does what it says on the tin, I didn't notice this had drifted this far.

[github-actions]

➿ Code coverage

Filename	Statements	Branches	Functions	Lines
src/Documents/BitmapGRF.ts	51.91%	35.71%	66.67%	53.91%
src/WebZlpError.ts	33.33%	100%	0%	33.33%
src/index.ts	100%	100%	100%	100%
src/Documents/Commands.ts	38.2%	46.88%	8.75%	38.07%
src/Printers/Configuration/PrinterOptions.ts	28.95%	66.67%	7.14%	28.95%
src/Printers/Models/PrinterModel.ts	42.86%	22.22%	6.67%	42.86%
src/Printers/Configuration/SerialPortSettings.ts	100%	100%	100%	100%
src/Printers/Configuration/MediaOptions.ts	70.77%	35.71%	71.43%	70.77%
src/Documents/ConfigDocument.ts	37.5%	0%	33.33%	37.5%
src/Documents/Document.ts	50%	0%	33.33%	55%
src/Documents/LabelDocument.ts	54.17%	66.67%	26.67%	54.17%
src/Documents/ReadyToPrintDocuments.ts	31.82%	100%	0%	33.33%
src/Printers/Communication/LineBreakTransformer.ts	12.5%	100%	0%	14.29%
src/Printers/Communication/PrinterCommunication.ts	84.62%	66.67%	66.67%	84.62%
src/Printers/Communication/UsbPrinterDeviceChannel.ts	7.04%	0%	0%	7.04%
src/Printers/Languages/EplPrinterCommandSet.ts	14.29%	8.47%	9.68%	14.97%
src/Printers/Models/PrinterModelDb.ts	18.52%	0%	0%	18.52%
src/Printers/Models/EplPrinterModels.ts	46.15%	100%	0%	46.15%
src/Printers/Languages/PrinterCommandSet.ts	22.45%	6.25%	12%	23.16%
src/Printers/PrinterCommunicationOptions.ts	25%	100%	100%	25%
src/Printers/Printer.ts	11.43%	0%	0%	11.54%
src/Printers/Languages/ZplPrinterCommandSet.ts	4.35%	0%	0%	4.38%
src/PrinterUsbManager.ts	6.52%	0%	0%	6.82%