In xml.etree.ElementTree docs there are many absent Element class links

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-09-21.10:27:48.726>
labels = ['expert-XML', '3.7', 'type-bug', 'library', 'docs']
title = 'In xml.etree.ElementTree docs there are many absent Element class links'
updated_at = <Date 2018-10-09.14:05:31.849>
user = 'https://github.com/py-user'

bugs.python.org fields:

activity = <Date 2018-10-09.14:05:31.849>
actor = 'serhiy.storchaka'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation', 'Library (Lib)', 'XML']
creation = <Date 2016-09-21.10:27:48.726>
creator = 'py.user'
dependencies = []
files = ['44775']
hgrepos = []
issue_num = 28234
keywords = ['patch']
message_count = 8.0
messages = ['277121', '277187', '277194', '277197', '277209', '277211', '277219', '277255']
nosy_count = 6.0
nosy_names = ['scoder', 'eli.bendersky', 'docs@python', 'py.user', 'martin.panter', 'serhiy.storchaka']
pr_nums = ['9766']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue28234'
versions = ['Python 2.7', 'Python 3.5', 'Python 3.6', 'Python 3.7']