doc: updated 3 man pages for 'LIBPROC_HIDE_KERNEL' var

This patch was prompted by Björn Fischer's merge #147
request referenced below. And since the library change
may impact all users, multiple man pages were updated.

[ and thanks to Björn for initiating this extension ]

Reference(s):
https://gitlab.com/procps-ng/procps/-/merge_requests/147

Prototyped-by: Björn Fischer <bf@CeBiTec.Uni-Bielefeld.DE>
Signed-off-by: Jim Warner <james.warner@comcast.net>

doc/procps_pids.3

@@ -205,6 +205,14 @@ This verification feature incurs substantial overhead.
 Therefore, it is important that it \fInot\fR be activated
 for a production/release build.
 
+.SH ENVIRONMENT VARIABLE(S)
+The value set for the following is unimportant, just its presence.
+
+.IP LIBPROC_HIDE_KERNEL
+This will hide kernel threads which would otherwise be returned with a
+.BR procps_get ", " procps_select " or " procps_reap
+call.
+
 .SH SEE ALSO
 .BR procps (3)
 .BR procps_misc (3)

ps/ps.1

@@ -4,7 +4,7 @@
 .\" Quick hack conversion by Albert Cahalan, 1998.
 .\" Licensed under version 2 of the Gnu General Public License.
 .\"
-.TH PS "1" "2021-06-16" "procps-ng" "User Commands"
+.TH PS "1" "January 2022" "procps-ng" "User Commands"
 .\"
 .\" To render this page:
 .\"    groff -t -b -man -X -P-resolution -P100 -Tps ps.1 &
@@ -1949,6 +1949,13 @@ Force obsolete command line interpretation.
 .B LC_TIME
 Date format.
 .TP
+.B LIBPROC_HIDE_KERNEL
+Set this to any value to hide kernel threads normally displayed with the
+.B -e
+option. This is equivalent to selecting
+.B --ppid 2 -p 2 --deselect
+instead. Also works in BSD mode.
+.TP
 .B PS_COLORS
 Not currently supported.
 .TP

top/top.1

@@ -131,12 +131,13 @@ The remaining Table of Contents
        b. ADDING INSPECT Entries
        c. SYSTEM Configuration File
        d. SYSTEM Restrictions File
-    7. STUPID TRICKS Sampler
+    7. ENVIRONMENT VARIABLE(S)
+    8. STUPID TRICKS Sampler
        a. Kernel Magic
        b. Bouncing Windows
        c. The Big Bird Window
        d. The Ol' Switcheroo
-    8. BUGS, 9. SEE Also
+    9. BUGS, 10. SEE Also
 .fi
 
 .\" ......................................................................
@@ -2518,9 +2519,17 @@ It should have exactly two lines, as shown in this example:
     5.0      # line 2: delay interval in seconds
 .fi
 
-.\" ......................................................................
 .\" ----------------------------------------------------------------------
-.SH 7. STUPID TRICKS Sampler
+.SH 7. ENVIRONMENT VARIABLE(S)
+.\" ----------------------------------------------------------------------
+The value set for the following is unimportant, just its presence.
+
+.IP LIBPROC_HIDE_KERNEL
+This will prevent display of any kernel threads and exclude such processes
+from the \*(SA Tasks/Threads counts.
+
+.\" ----------------------------------------------------------------------
+.SH 8. STUPID TRICKS Sampler
 .\" ----------------------------------------------------------------------
 Many of these tricks work best when you give \*(We a scheduling boost.
 So plan on starting him with a nice value of \-10, assuming you've got
@@ -2641,14 +2650,14 @@ of travel for the command lines being shown.
    eventually all lines will Switcheroo, and move right
 
 .\" ----------------------------------------------------------------------
-.SH 8. BUGS
+.SH 9. BUGS
 .\" ----------------------------------------------------------------------
 Please send bug reports to
 .UR procps@freelists.org
 .UE .
 
  \" ----------------------------------------------------------------------
-.SH 9. SEE Also
+.SH 10. SEE Also
 .\" ----------------------------------------------------------------------
 .BR free (1),
 .BR ps (1),