doctest syntax ambiguity between continuation line and ellipsis

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-01-07.04:05:17.271>
labels = ['3.8', 'type-bug', 'library']
title = 'doctest syntax ambiguity between continuation line and ellipsis'
updated_at = <Date 2021-02-08.00:11:09.958>
user = 'https://github.com/jaraco'

bugs.python.org fields:

activity = <Date 2021-02-08.00:11:09.958>
actor = 'jaraco'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-01-07.04:05:17.271>
creator = 'jaraco'
dependencies = []
files = []
hgrepos = []
issue_num = 32509
keywords = []
message_count = 15.0
messages = ['309599', '309600', '309601', '309602', '309603', '309604', '309605', '309606', '309611', '309622', '309630', '309631', '342372', '385154', '386610']
nosy_count = 5.0
nosy_names = ['tim.peters', 'jaraco', 'steven.daprano', 'r.david.murray', 'mblahay']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue32509'
versions = ['Python 3.8']