correct Research Unix edition "appeared in" use in HISTORY

Starting from "Combined Table of Contents" in Doug McIlroy's
"A Research UNIX Reader" a table of which edition manuals appeared in.
Checked against manuals from bitsavers/TUHS and source from TUHS where
available.

Ingo points out there are cases where something is included but not
documented until a later release.
bcd(6)		v6	v7
printf(3)	v2	v4
abort(3)	v5	v6
system(3)	v6	v7
fmod(3)		v5	v6

ok schwarze@

2 files changed, 6 insertions, 6 deletions

diff --git a/lib/libc/sys/intro.2 b/lib/libc/sys/intro.2
index b2069bfba7d..6f96c020dca 100644
--- a/lib/libc/sys/intro.2
+++ b/lib/libc/sys/intro.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: intro.2,v 1.68 2018/09/30 13:24:33 schwarze Exp $
+.\"	$OpenBSD: intro.2,v 1.69 2020/02/08 01:09:57 jsg Exp $
 .\"	$NetBSD: intro.2,v 1.6 1995/02/27 12:33:41 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1983, 1986, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)intro.2	8.3 (Berkeley) 12/11/93
 .\"
-.Dd $Mdocdate: September 30 2018 $
+.Dd $Mdocdate: February 8 2020 $
 .Dt INTRO 2
 .Os
 .Sh NAME
@@ -743,4 +743,4 @@ socket was created.
 An
 .Nm
 manual for section 2 first appeared in
-.At v6 .
+.At v5 .
diff --git a/lib/libc/sys/kill.2 b/lib/libc/sys/kill.2
index 20bdf56af0b..f12cc4b03dc 100644
--- a/lib/libc/sys/kill.2
+++ b/lib/libc/sys/kill.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: kill.2,v 1.25 2017/05/06 22:37:43 millert Exp $
+.\"	$OpenBSD: kill.2,v 1.26 2020/02/08 01:09:57 jsg Exp $
 .\"	$NetBSD: kill.2,v 1.7 1995/02/27 12:33:53 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)kill.2	8.3 (Berkeley) 4/19/94
 .\"
-.Dd $Mdocdate: May 6 2017 $
+.Dd $Mdocdate: February 8 2020 $
 .Dt KILL 2
 .Os
 .Sh NAME
@@ -161,7 +161,7 @@ function conforms to
 The
 .Fn kill
 system call first appeared in
-.At v3 .
+.At v2 .
 The
 .Fa sig
 argument was introduced in