[blank] visible in some outputs when NO_COLOR is set

[tuurep]

Hello, I would have sent a simple PR but I'm not quite sure how to fix after looking at it.

I found two contexts where [blank] gets printed:

NO_COLOR="Yup" cb copy "123"

Outputs ✅ Copied text "123"[blank]

NO_COLOR="Yup" cb show

Outputs • Here are the first 3 bytes in clipboard 0: [blank]123

Note: cb copy doesn't show the [blank] when copying something other than a string, but cb show will show it regardless of what's in the clipboard

[Slackadays]

@tuurep Fixed back in f41fc48

[tuurep]

Ah, I see. Thank you :)