inspect.getdoc/.cleandoc doesn't always remove trailing blank lines

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-08-30.22:53:18.157>
labels = ['3.8', 'type-bug', 'library', '3.9', '3.10']
title = "inspect.getdoc/.cleandoc doesn't always remove trailing blank lines"
updated_at = <Date 2020-09-04.23:01:21.440>
user = 'https://bugs.python.org/RalfM'

bugs.python.org fields:

activity = <Date 2020-09-04.23:01:21.440>
actor = 'terry.reedy'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-08-30.22:53:18.157>
creator = 'RalfM'
dependencies = []
files = []
hgrepos = []
issue_num = 41671
keywords = []
message_count = 1.0
messages = ['376136']
nosy_count = 2.0
nosy_names = ['yselivanov', 'RalfM']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue41671'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']