Fix test__locale on Mac; platform.uname() does not have a structseq-type interface (yet).
diff --git a/Doc/library/email.headerregistry.rst b/Doc/library/email.headerregistry.rst
index af72b7c..c884159 100644
--- a/Doc/library/email.headerregistry.rst
+++ b/Doc/library/email.headerregistry.rst
@@ -16,7 +16,7 @@
necessary by the core developers.
.. versionadded:: 3.3
- as a :term:`provisional module <provisional package>`
+ as a :term:`provisional module <provisional package>`.
Headers are represented by customized subclasses of :class:`str`. The
particular class used to represent a given header is determined by the