Add hint for federated sharing

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

apps/federatedfilesharing/templates/settings-personal.php

@@ -8,6 +8,7 @@ style('federatedfilesharing', 'settings-personal');
 <?php if ($_['outgoingServer2serverShareEnabled']): ?>
 	<div id="fileSharingSettings" class="section">
 		<h2><?php p($l->t('Federated Cloud')); ?></h2>
+		<p class="settings-hint"><?php p($l->t('You can share with anyone who uses Nextcloud, ownCloud or Pydio! Just put their Federated Cloud ID in the share dialog. It looks like person@cloud.example.com')); ?></p>
 
 		<p>
 			<?php p($l->t('Your Federated Cloud ID:')); ?>