[m-rev.] diff: adjust the release notes

[Julien Fischer]

The lists of systems we have tested on (currently) covers only the ones
I have tested; Peter, do you have any others?

Julien.

---------------------------------------

Adjust the release notes.

RELEASE_NOTES:
     Adjust the list of systems we have tested on.

README.MacOS:
     Be clear that this document covers all version of macOS.


diff --git a/README.MacOS b/README.MacOS
index 22e4dfb..9fff796 100644
--- a/README.MacOS
+++ b/README.MacOS
@@ -1,4 +1,4 @@
-This file documents the port of Mercury to Mac OS X,
+This file documents the port of Mercury to Mac OS X / OS X / macOS,
  i.e. the "*-apple-darwin*" configuration.

  --------
diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 8d0ba9b..5525ef7 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -145,9 +145,7 @@ Erlang.  See README.Java, README.CSharp, and README.Erlang respectively
  for further details.

  The current Mercury system has been tested on Linux (x86 and x86_64),
-Mac OS X (x86 and x86_64), and Windows (x86 and x86_64).
-For Windows, we have tested this release on Windows XP SP3, Windows 7,
-and Windows Server 2008 R2.
+macOS (x86_64), and Windows (x86 and x86_64).

  In the past Mercury has also been known to run on: Digital Unix,
  OSF1, IRIX 5.x, Ultrix 4.3, BSDI 1.1, AIX, HPUX, Linux (Alpha),