Fix typo in comment, handeling->handling

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <guss80@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: bunder2015 <omfgbunder@gmail.com>
Signed-off-by: Kash Pande <kash@tripleback.net>
Closes #7641

cmd/zed/zed_disk_event.c

@@ -37,7 +37,7 @@
  * A libudev monitor is established to monitor block device actions and pass
  * them on to internal ZED logic modules.  Initially, zfs_mod.c is the only
  * consumer and is the Linux equivalent for the illumos syseventd ZFS SLM
- * module responsible for handeling disk events for ZFS.
+ * module responsible for handling disk events for ZFS.
  */
 
 pthread_t g_mon_tid;