IDLE: Fix tab completion after settings and some keys

GitHub fields:

assignee = 'https://github.com/terryjreedy'
closed_at = None
created_at = <Date 2021-03-29.08:40:35.880>
labels = ['expert-IDLE', 'type-bug', '3.9', '3.10', '3.11']
title = 'IDLE: Fix tab completion after settings and some keys'
updated_at = <Date 2022-01-20.19:56:17.994>
user = 'https://github.com/terryjreedy'

bugs.python.org fields:

activity = <Date 2022-01-20.19:56:17.994>
actor = 'taleinat'
assignee = 'terry.reedy'
closed = False
closed_date = None
closer = None
components = ['IDLE']
creation = <Date 2021-03-29.08:40:35.880>
creator = 'terry.reedy'
dependencies = []
files = []
hgrepos = []
issue_num = 43654
keywords = ['patch']
message_count = 13.0
messages = ['389673', '389791', '390731', '390732', '390755', '390824', '394542', '394545', '394631', '394883', '395063', '395201', '411043']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'rhettinger', 'terry.reedy', 'taleinat', 'tetelevm']
pr_nums = ['26403', '26421']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue43654'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']