bpo-35035: Rename email.utils documentation to email.utils.rst (GH-10023)

I'll watch for 404 on the old URL and will setup an HTTP redirection if needed.
diff --git a/Doc/library/email.rst b/Doc/library/email.rst
index 07d455b..fae99cf 100644
--- a/Doc/library/email.rst
+++ b/Doc/library/email.rst
@@ -126,7 +126,7 @@
    email.header.rst
    email.charset.rst
    email.encoders.rst
-   email.util.rst
+   email.utils.rst
    email.iterators.rst
 
 
diff --git a/Doc/library/email.util.rst b/Doc/library/email.utils.rst
similarity index 100%
rename from Doc/library/email.util.rst
rename to Doc/library/email.utils.rst
diff --git a/Misc/NEWS.d/next/Documentation/2018-10-21-02-20-36.bpo-35035.4zBObK.rst b/Misc/NEWS.d/next/Documentation/2018-10-21-02-20-36.bpo-35035.4zBObK.rst
new file mode 100644
index 0000000..46436f1
--- /dev/null
+++ b/Misc/NEWS.d/next/Documentation/2018-10-21-02-20-36.bpo-35035.4zBObK.rst
@@ -0,0 +1 @@
+Rename documentation for :mod:`email.utils` to ``email.utils.rst``.