zinject(8): rename "ioctl" to "flush"

Doc bug missed in d7605ae.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes openzfs#16827

man/man8/zinject.8

@@ -23,7 +23,7 @@
 .\"
 .\" lint-ok: WARNING: sections out of conventional order: Sh SYNOPSIS
 .\"
-.Dd April 4, 2024
+.Dd December 2, 2024
 .Dt ZINJECT 8
 .Os
 .
@@ -268,7 +268,7 @@ Run for this many seconds before reporting failure.
 .It Fl T Ar failure
 Set the failure type to one of
 .Sy all ,
-.Sy ioctl ,
+.Sy flush ,
 .Sy claim ,
 .Sy free ,
 .Sy read ,