Fix macro playback crash issue

The crash issue is due to a mutex locked twice which should be a dead lock but a "device or resource busy" exception is lauched:
https://stackoverflow.com/questions/16664375/why-locking-a-stdmutex-doesnt-block-the-thread

From 7.8 the standard mutex is used, that changes the behaviour.

PowerEditor/src/NppCommands.cpp

@@ -47,8 +47,6 @@ std::mutex command_mutex;
 
 void Notepad_plus::macroPlayback(Macro macro)
 {
-	std::lock_guard<std::mutex> lock(command_mutex);
-
 	_playingBackMacro = true;
 	_pEditView->execute(SCI_BEGINUNDOACTION);