Markup correction.

docs/background/releases.rst

@@ -9,7 +9,7 @@ Release History
 * Removed automatic conversion of ``NSString`` objects to ``str`` when returned from Objective-C methods. This feature made it difficult to call Objective-C methods on ``NSString`` objects, because there was no easy way to prevent the automatic conversion.
   * In most cases, this change will not affect existing code, because ``NSString`` objects now support operations similar to ``str``.
   * If an actual ``str`` object is required, the ``NSString`` object can be wrapped in a ``str`` call to convert it.
-* Added support for ``objc_property``s with non-object types.
+* Added support for ``objc_property`` with non-object types.
 * Added public ``get_ivar`` and ``set_ivar`` functions for manipulating ivars.
 * Changed the implementation of ``objc_property`` to use ivars instead of Python attributes for storage. This fixes name conflicts in some situations.
 * Fixed ``objc_property`` setters on non-macOS platforms. (cculianu)