ntpath.relpath behaves differently on Windows with trailing spaces

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-08-08.17:34:37.931>
labels = ['3.8', 'OS-windows']
title = 'ntpath.relpath behaves differently on Windows with trailing spaces'
updated_at = <Date 2020-08-08.19:15:05.636>
user = 'https://github.com/jaraco'

bugs.python.org fields:

activity = <Date 2020-08-08.19:15:05.636>
actor = 'eryksun'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Windows']
creation = <Date 2020-08-08.17:34:37.931>
creator = 'jaraco'
dependencies = []
files = []
hgrepos = []
issue_num = 41509
keywords = []
message_count = 2.0
messages = ['375053', '375058']
nosy_count = 6.0
nosy_names = ['paul.moore', 'jaraco', 'tim.golden', 'zach.ware', 'eryksun', 'steve.dower']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue41509'
versions = ['Python 3.8']