Fix old bug #58936

[Rafael Fontenelle]

Hi all,

The bug #58936 [1] seems to be an easy fix, yet impacts the
man-page-l10n project (as mentioned in the bug report). Looks like
simply removing the vertical tab (\v) from grub-mknetdir.c [2] is
enough. Can you please take a look at it?

[1] https://savannah.gnu.org/bugs/?58936
[2] https://git.savannah.gnu.org/cgit/grub.git/tree/util/grub-mknetdir.c#n90

Thanks in advance,
Rafael