Fix the context menu needs restarting explorer to appear issue under Win 8/10

[donho]

Fix the context menu needs restarting explorer to appear issue after updating from the old NppShell_06.dll to new NppShell.dll.

The fix is to not unregister the old one so the old context menu still working until user restarting explorer or windows, then the old context menu disappears and the new one appears.

Fix #13

[donho]

@GurliGebis Could you review this PR?

Also here's the newest packages TEST11: http://download.notepad-plus-plus.org/repository/MISC/nppShell.TEST11/

[donho]

Test results of updating from v8.4.9 (NppShell_06.dll) to TEST11 (new NppShell.dll):

• Windows 8.1 Pro 64-bits: PASSED
• Windows 10 Pro 64-bits: PASSED
• Windows 11 Home 64-bits: FAILED (2 Edit with Notepad++ entries in Show more option)

[GurliGebis]

@donho there is a small problem with Windows 11:

But we can do it in another way - try with #15 instead.

It does the following:

• Skips unregistering on Windows 10 and below.
• Schedules the dll files for removal at next reboot instead of moving to the temp folder and then schedule. (By commenting out those calls, the files doesn't get moved away).
• Unregisters the old context menu on Windows 11, to avoid the double entries shown in the screenshot above.

[sincereman]

I have the same problem in 8.5.2 and 8.5.3 version (open multiple text document from context menu and the system is need to restart). Last version without this problem 8.5.

[GurliGebis]

@sincereman I just tested it on Windows 10, and it seems to be working fine. Can you create a new issue about it, and if possible, with a bit more info (Windows build number, which version is installed already if upgrading, steps etc.)