Add history section for echo(1)

Sourced using the draft copy of the second edition manual
http://www.tuhs.org/Archive/PDP-11/Distributions/research/1972_stuff/unix_2nd_edition_manual.pdf

PR:		211785
Approved by:	bcr (mentor)
MFC after:	5 days
Differential Revision:	https://reviews.freebsd.org/D8104

bin/echo/echo.1

@@ -32,7 +32,7 @@
 .\"	@(#)echo.1	8.1 (Berkeley) 7/22/93
 .\" $FreeBSD$
 .\"
-.Dd November 12, 2010
+.Dd October 5, 2016
 .Dt ECHO 1
 .Os
 .Sh NAME
@@ -103,3 +103,8 @@ The
 utility conforms to
 .St -p1003.1-2001
 as amended by Cor.\& 1-2002.
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.At v2 .