replace "Mac OS X" and "OS X" with "macOS"

as it is the official name since 2016

https://en.wikipedia.org/wiki/Macintosh_operating_systems#Desktop

exception are parts refering to older versions of macOS like

"GUI support for Mac OS X 10.6 - 10.12. Note that Emacs 23 and later [...]"

pkgs/development/libraries/hunspell/default.nix

@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
     longDescription = ''
       Hunspell is the spell checker of LibreOffice, OpenOffice.org, Mozilla
       Firefox 3 & Thunderbird, Google Chrome, and it is also used by
-      proprietary software packages, like Mac OS X, InDesign, memoQ, Opera and
+      proprietary software packages, like macOS, InDesign, memoQ, Opera and
       SDL Trados.
 
       Main features:
@@ -38,7 +38,7 @@ stdenv.mkDerivation rec {
       * C++ library under GPL/LGPL/MPL tri-license.
       * Interfaces and ports:
         * Enchant (Generic spelling library from the Abiword project),
-        * XSpell (Mac OS X port, but Hunspell is part of the OS X from version 10.6 (Snow Leopard), and
+        * XSpell (macOS port, but Hunspell is part of the macOS from version 10.6 (Snow Leopard), and
             now it is enough to place Hunspell dictionary files into
             ~/Library/Spelling or /Library/Spelling for spell checking),
         * Delphi, Java (JNA, JNI), Perl, .NET, Python, Ruby ([1], [2]), UNO.