patch 8.2.2450: MS-Windows: ADS was not preserved if 'backupcopy' is "yes"

Problem:    MS-Windows: ADS was not preserved if 'backupcopy' is "yes".
Solution:   Copy ADS before truncating the file. (Ken Takata, closes #7762)
diff --git a/src/bufwrite.c b/src/bufwrite.c
index d7c74de..c7c832c 100644
--- a/src/bufwrite.c
+++ b/src/bufwrite.c
@@ -1497,6 +1497,9 @@
 #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
 			mch_copy_sec(fname, backup);
 #endif
+#ifdef MSWIN
+			(void)mch_copy_file_attribute(fname, backup);
+#endif
 			break;
 		    }
 		}
@@ -1909,12 +1912,7 @@
 
 #if defined(MSWIN)
 	    if (backup != NULL && overwriting && !append)
-	    {
-		if (backup_copy)
-		    (void)mch_copy_file_attribute(wfname, backup);
-		else
-		    (void)mch_copy_file_attribute(backup, wfname);
-	    }
+		(void)mch_copy_file_attribute(backup, wfname);
 
 	    if (!overwriting && !append)
 	    {