I have a basic question on child themes. I know the benefit of using them is that your changes will remain if the theme it is based on is updated. I have followed the Codex and made created a functions.php file inside my child theme directory. However, what if I make changes to the original theme's non-functions.php files, such as header.php and footer.php. Do these changes get wiped out if the theme is later updated? I am just modifying the copyright wording in the footer.