Fix append extension issue when use Korean IME(letter composition bug).

[80ROkWOC4j]

Fix Korean IME issue #11582

I test this on Korean Windows and it works fine, but Japanese/Chinese Windows IME might need to be tested too.

I've been trying to find when the IME ends input, but i can't find the way. Even "WM_IME_ENDCOMPOSITION" is detected before the composition is complete. So I choose dirty way. Please consider change hooking keyboard to something else if this PR makes another problems.

[yasmise]

@80ROkWOC4j
I tried AppVeyor's build with this PR, and this has a bad side effect for Japanese IME. (With Japanese IME, issue #11582 does not happen).

Original release of Ver. 8.4.3 works like this:

1. Save new file with Ctrl + S.
2. Input aiueo with Japanese IME, then IME displays あいうえお.
3. Hit Enter key, then field of filename is changed to あいうえお.txt.
4. Hit Enter key to save file.

With this PR:

1. Same as above.
2. Same as above.
3. Hit Enter key, then save-dialog is closed and the file is saved. Filename is correctly set to あいうえお.txt.

Debug info:
Notepad++ v8.4.3 (64-bit)
Build time : Jul 7 2022 - 10:55:58
Path : C:\Program Files\Notepad++\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 11 (64-bit)
OS Version : 21H2
OS Build : 22000.795
Current ANSI codepage : 932
Plugins :
mimeTools (2.5)
NppConverter (4.2.1)
NppExport (0.2.9)

[donho]

@80ROkWOC4j
A regression has pointed out by @yasmise , and OTOH, I am doubting there are other regression since KbdProcHook has been modified heavily.

As a result, this PR cannot be accepted. Feel free to provide another one if you have simpler solution which doesn't bring any regression.

[80ROkWOC4j]

Thanks for @yasmise 's test. Contrary to my expectation, this seems to occur only in Korean IME, not CJK, due to the difference in candidate (composition) behavior.
I've also tried rolling back hooking keyboard#, but this doesn't seem to work because I ran into another problem.
In order to fix the #issue while maintaining the hooking keyobard and Add Extension feature, it seems to be necessary to create a logic that works only for Korean IME, not the CJK.