chore: Add comment to make code clearer

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

lib/private/Share20/Manager.php

@@ -1101,6 +1101,7 @@ class Manager implements IManager {
 
 		foreach ($reshareRecords as $child) {
 			try {
+				/* Check if the share is still valid (means the resharer still has access to the file through another mean) */
 				$this->generalCreateChecks($child);
 			} catch (GenericShareException $e) {
 				/* The check is invalid, promote it to a direct share from the sharer of parent share */