[m-rev.] diff: fic description in samples README

[Julien Fischer]

Fix description in samples README.

samples/REAMDE.md:
     Fix the description of the 'sort' sample, which hasn't actually
     reflected what that sample did since the description was added.

Julien.

diff --git a/samples/README.md b/samples/README.md
index a112b13..9e2ce39 100644
--- a/samples/README.md
+++ b/samples/README.md
@@ -10,9 +10,9 @@ This directory contains some example Mercury programs.
    to the standard output stream.

  * [sort.m](sort.m) -- An implementation of a simple version of the standard
-  UNIX filter `sort`, which reads lines from its input files or the standard
-  input stream, sorts them, and then writes the result to the standard output
-  stream.
+  UNIX filter `sort`, which reads lines from its input file or the standard
+  input stream, sorts them, and then writes the result to its output file or
+  the standard output stream.

  * [calculator.m](calculator.m) -- A simple four-function arithmetic calculator,
    with a parser written using Definite Clause Grammar (DCG) notation.