patch 8.2.4170: MS-Windows: still using old message API calls

Problem:    MS-Windows: still using old message API calls.
Solution:   Call the "W" functions directly. (Ken Takata, closes #9582)
diff --git a/src/os_win32.c b/src/os_win32.c
index 55df506..ae66652 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -4123,10 +4123,10 @@
 	{
 	    MSG	msg;
 
-	    if (pPeekMessage(&msg, (HWND)NULL, 0, 0, PM_REMOVE))
+	    if (PeekMessageW(&msg, (HWND)NULL, 0, 0, PM_REMOVE))
 	    {
 		TranslateMessage(&msg);
-		pDispatchMessage(&msg);
+		DispatchMessageW(&msg);
 		delay = 1;
 		continue;
 	    }
@@ -4445,10 +4445,10 @@
     {
 	MSG	msg;
 
-	if (pPeekMessage(&msg, (HWND)NULL, 0, 0, PM_REMOVE))
+	if (PeekMessageW(&msg, (HWND)NULL, 0, 0, PM_REMOVE))
 	{
 	    TranslateMessage(&msg);
-	    pDispatchMessage(&msg);
+	    DispatchMessageW(&msg);
 	}
 
 	// write pipe information in the window