bug#46979: Allow setting Man-default-entry via Local Variables

[Eli Zaretskii]

> From: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
> Cc: mardani29@yahoo.es,  46979@debbugs.gnu.org
> Date: Tue, 09 Mar 2021 01:06:32 +0800
> 
> >>>>> "EZ" == Eli Zaretskii <eliz@gnu.org> writes:
> EZ> Who on earth needs to read the man page of crontab(5)?
> 
> How then, do you remember the order of the five numbers on each line?
> Is the first the minute, or the hour, etc.
> 
> Also crontab doesn't have an Info manual.
> 
> Anyway, if someone wrote the crontab(5) man page, that probably means it
> exists for a reason.
> 
> Same say for fstab(5).

OK, but why do you insist on doing this via file-local variables?