reg: Add missing null to terminate a string.

programs/reg/export.c

@@ -316,7 +316,7 @@ static void export_file_header(HANDLE hFile)
 {
     static const WCHAR header[] = { 0xfeff,'W','i','n','d','o','w','s',' ',
                                    'R','e','g','i','s','t','r','y',' ','E','d','i','t','o','r',' ',
-                                   'V','e','r','s','i','o','n',' ','5','.','0','0','\r','\n'};
+                                   'V','e','r','s','i','o','n',' ','5','.','0','0','\r','\n',0};
 
     write_file(hFile, header);
 }