IDLE: Handle Shell input SyntaxWarning & DeprecationWarning

GitHub fields:

assignee = 'https://github.com/terryjreedy'
closed_at = None
created_at = <Date 2019-08-11.16:32:12.488>
labels = ['3.8', 'expert-IDLE', 'type-bug', '3.7', '3.9']
title = 'IDLE: Handle Shell input SyntaxWarning & DeprecationWarning'
updated_at = <Date 2021-11-12.19:21:29.683>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2021-11-12.19:21:29.683>
actor = 'terry.reedy'
assignee = 'terry.reedy'
closed = False
closed_date = None
closer = None
components = ['IDLE']
creation = <Date 2019-08-11.16:32:12.488>
creator = 'serhiy.storchaka'
dependencies = []
files = []
hgrepos = []
issue_num = 37824
keywords = ['patch']
message_count = 19.0
messages = ['349396', '349441', '349846', '349858', '349869', '349884', '349896', '350483', '350487', '350492', '350494', '369929', '369934', '370163', '370212', '370357', '370358', '386622', '406234']
nosy_count = 6.0
nosy_names = ['rhettinger', 'terry.reedy', 'taleinat', 'serhiy.storchaka', 'cheryl.sabella', 'miss-islington']
pr_nums = ['15311', '15500', '15504', '15505']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue37824'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']