gh-101863: Fix wrong comments in EUC-KR codec

[b8choi]

This PR fix the wrong comments in the code related to #101863.

The encoding method using "Hangul Filler" is defined in subclause 4.3 of KS X 1001, whereas Annex 3 defines an alternative 2-byte Johab code.

• Issue: euc_kr char '0x3164' decode('ksx1001') cause UnicodeDecodeError  #101863

[bedevere-bot]

Most changes to Python require a NEWS entry.

Please add it using the blurb_it web app or the blurb command-line tool.

[cpython-cla-bot]

All commit authors signed the Contributor License Agreement.

[corona10]

Please add your name to the following file.

cpython/Misc/ACKS

Lines 324 to 325 in 8de59c1

	Kit Yan Choi
	Sayan Chowdhury

[bedevere-bot]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[corona10]

lgtm

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM64 macOS 3.x has failed when building commit 77a3196.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/725/builds/3847) and take a look at the build logs.
4. Check if the failure is related to this commit (77a3196) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/725/builds/3847

Failed tests:

• test_asyncio

Failed subtests:

• test_wait_for_race_condition - test.test_asyncio.test_waitfor.AsyncioWaitForTest.test_wait_for_race_condition

Summary of the results of the build (if available):

== Tests result: FAILURE then FAILURE ==

405 tests OK.

10 slowest tests:

• test_concurrent_futures: 2 min 38 sec
• test_multiprocessing_spawn: 2 min 9 sec
• test_ssl: 1 min 47 sec
• test_multiprocessing_forkserver: 1 min 35 sec
• test_asyncio: 1 min 30 sec
• test_logging: 1 min 15 sec
• test_math: 1 min 7 sec
• test_capi: 47.4 sec
• test_signal: 46.5 sec
• test_io: 39.7 sec

1 test failed:
test_asyncio

25 tests skipped:
test_check_c_globals test_devpoll test_epoll test_gdb test_idle
test_ioctl test_launcher test_msilib test_multiprocessing_fork
test_ossaudiodev test_peg_generator test_perf_profiler test_spwd
test_startfile test_tcl test_tix test_tkinter test_ttk
test_ttk_textonly test_turtle test_winconsoleio test_winreg
test_winsound test_wmi test_zipfile64

1 re-run test:
test_asyncio

Total duration: 7 min 30 sec

Click to see traceback logs

Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/asyncio/tasks.py", line 478, in wait_for
    return await fut
           ^^^^^^^^^
asyncio.exceptions.CancelledError


Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/unittest/async_case.py", line 90, in _callTestMethod
    if self._callMaybeAsync(method) is not None:
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/unittest/async_case.py", line 112, in _callMaybeAsync
    return self._asyncioRunner.run(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/asyncio/base_events.py", line 664, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/test/test_asyncio/test_waitfor.py", line 163, in test_wait_for_race_condition
    res = await task
          ^^^^^^^^^^
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/asyncio/tasks.py", line 477, in wait_for
    async with timeouts.timeout(timeout):
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/asyncio/timeouts.py", line 98, in __aexit__
    raise TimeoutError
TimeoutError