bug#36729: 27.0.50; Unclear total in directory listing

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Fri, 19 Jul 2019 12:15:58 +0200
> 
> The first line of a directory listing reads
> 
>   total used in directory 71752 available 65.2 GiB
> 
> where it is a mystery what the first number represents. Often it is 512-byte 
> blocks, which is confusing and not very useful, and cannot easily be compared 
> with the 'available' number (which is crystal clear).

Feel free to suggest a clarification in the doc string of 'dired'.