Be on brand: it's macOS (#3456)

* Be on brand: it's macOS

* line wrap
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 22807f1..897a05c 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -92,7 +92,7 @@
 OS random sources
 -----------------
 
-On OS X and FreeBSD ``/dev/urandom`` is an alias for ``/dev/random`` and
+On macOS and FreeBSD ``/dev/urandom`` is an alias for ``/dev/random`` and
 utilizes the `Yarrow`_ algorithm.
 
 On Windows the implementation of ``CryptGenRandom`` depends on which version of