Networks and Sites: Use numbered placeholder in a mailto: link in ms_site_check().

Props diddledan.
Fixes #46849.

git-svn-id: https://develop.svn.wordpress.org/trunk@45162 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/ms-load.php

@@ -109,7 +109,7 @@ function ms_site_check() {
 				/* translators: %s: admin email link */
 				sprintf(
 					__( 'This site has not been activated yet. If you are having problems activating your site, please contact %s.' ),
-					sprintf( '<a href="mailto:%s">%s</a>', $admin_email )
+					sprintf( '<a href="mailto:%1$s">%1$s</a>', $admin_email )
 				)
 			);
 		}