[PATCH] manual: Fixed typo in manual/stdio.texi [BZ #24638]

[Girish Joshi]

Thanks Florian,

> Do you want to fix the other issue as well?  The missing declaration of
> the variable i, and the incorrect argument list for the error function?

Sure. I'll be happy to do that.
Could you please provide some pointers?

Girish Joshi.