Some deprecated ElementTree features are deprecated only in the documentation or in Python implementation (that is virtually the same since C implementation is default). Proposed patch adds missed deprecations is code. It also makes warnings be ignored only in tests where they are expected. This is possible since converting doctests to unittests some time ago.

Added deprecations:

* Element.getchildren() and Element.getiterator() methods. They were deprecated in the documentation and in Python implementation in 2.7 and 3.2.

* The xml.etree.cElementTree module. Deprecated in the documentation in 3.3.

* The html argument of XMLParser. Deprecated in the documentation in 3.4.

Ned, is it appropriate to commit the patch (or its part) in 3.6? The discrepancy between Python and C implementation can be considered as a bug. What are your thoughts?