Always display vendor & product IDs in left-padded 4-digit format

Unfortunately, C++ (and consequently Qt) lacks sane string formatting API, leaving us with the only option: to use a dummy "%1" arg string.

Why: because it would be easier to Ctrl+C Ctrl+F search things if everyone were to use the same format. And just why would you not use a fixed format for a 16-bytes fixed identifier?

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_{I should stop sending new patches until I finish sorting out the old ones...}