shelf in with stmt, fish/csh in venv, ElementTree short_empty_elements keyword.

Also added versionadded for for fish/csh, fixed indentation of versionadded
for ElementTree.write, and make the behavior of shelf as a context manager
explicit in the docs.
diff --git a/Doc/library/xml.etree.elementtree.rst b/Doc/library/xml.etree.elementtree.rst
index 4c89dc3..0731cd8 100644
--- a/Doc/library/xml.etree.elementtree.rst
+++ b/Doc/library/xml.etree.elementtree.rst
@@ -831,8 +831,8 @@
       :term:`file object`; make sure you do not try to write a string to a
       binary stream and vice versa.
 
-   .. versionadded:: 3.4
-      The *short_empty_elements* parameter.
+      .. versionadded:: 3.4
+         The *short_empty_elements* parameter.
 
 
 This is the XML file that is going to be manipulated::