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

* Be on brand: it's macOS

* line wrap
diff --git a/docs/security.rst b/docs/security.rst
index ff0a84a..67c3d33 100644
--- a/docs/security.rst
+++ b/docs/security.rst
@@ -64,7 +64,7 @@
 --------------------------------
 
 As of version 0.5, ``cryptography`` statically links OpenSSL on Windows, and as
-of version 1.0.1 on OS X, to ease installation. Due to this, ``cryptography``
+of version 1.0.1 on macOS, to ease installation. Due to this, ``cryptography``
 will release a new version whenever OpenSSL has a security or bug fix release to
 avoid shipping insecure software.