You could do something like:
$content .= html( 'p', sprintf(
__( 'Your "%s" listing claim has been approved.<br>Another line of text, go to <a href="www.linksite.com">This Website</a> for more...
You could do something like:
$content .= html( 'p', sprintf(
__( 'Your "%s" listing claim has been approved.<br>Another line of text, go to <a href="www.linksite.com">This Website</a> for more...
If you want it hidden from users, you can use this CSS
