sysctl(8): clarify -n flag

-n omits the name of the variable regardless of the type of information that is
requested. Rephrase to clarify this point.

PR:	242191
Submitted by:	stilezy@gmail.com
Approved by:	emaste@
Differential Revision:	https://reviews.freebsd.org/D26149

sbin/sysctl/sysctl.8

@@ -28,7 +28,7 @@
 .\"	From: @(#)sysctl.8	8.1 (Berkeley) 6/6/93
 .\" $FreeBSD$
 .\"
-.Dd February 8, 2019
+.Dd August 22, 2020
 .Dt SYSCTL 8
 .Os
 .Sh NAME
@@ -123,7 +123,7 @@ use:
 .Pp
 .Dl "complete sysctl 'n/*/`sysctl -Na`/'"
 .It Fl n
-Show only variable values, not their names.
+Do not show variable names.
 This option is useful for setting shell variables.
 For instance, to save the pagesize in variable
 .Va psize ,