bug#34026: mention that long options aren't always as good as short options

[積丹尼 Dan Jacobson]

On (info "(coreutils) Common options")
mention that, though clearer, long options aren't always as good as short 
options,
$ touch --reference=~jidanni/.pcmanx /cf/pcmanx_time
touch: failed to get attributes of '~jidanni/.pcmanx/pcmanx': No such file or 
directory
Unless one removes the '=':
$ touch --reference ~jidanni/.pcmanx/pcmanx /cf/pcmanx_time
$
(due to the shell helping out with "~...")