Different behaviour when using @macro with @sp, @vskip, @noindent

[Christopher Dimech]

I have the following texinfo code.  But if I put the same commands
in @macro, I see more vertical space when displaying the example
when calling the @macro Tuni.

@macro Tuni{sp,sk}
@iftex
  @sp \sp\
  @vskip \sk\
@end iftex
@noindent
@end macro

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Key Shortcuts are grouped into units called Key Input
Events.

@c @Tuni{0,2mm}
@iftex
@sp 0
@vskip 2mm
@end iftex
@noindent

@example
  (global-set-key (kbd "C-t <left>")  #'IntchgStc-Prev)
@end example
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