`NameError` has different actions when be raised in IDLE

Bug report

Bug description:

In IDLE, I raised three different exceptions. The output is:

>>>raise Exception("123\n456")
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    raise Exception("123\n456")
Exception: 123
456
>>>raise NameError("123\n456")
Traceback (most recent call last):
  File "<pyshell#1>", line 1, in <module>
    raise NameError("123\n456")
456
>>>raise OSError("123\n456")
Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    raise OSError("123\n456")
OSError: 123
456

Only NameError cannot show the Exception Type if the text has two or more lines.
In shell the action is same with other exception.

CPython versions tested on:

3.13

Operating systems tested on:

Windows

Linked PRs

• gh-135526

Start by reproducing the three exception cases in the IDLE shell on Python 3.13 and compare them with the regular shell output. Trace how IDLE formats multiline exception messages, then verify that a multiline NameError displays its exception type consistently with Exception and OSError; linked PR gh-135526 indicates work is already underway.