Improve wording when describing -mmin.

PR:		215922
Submitted by:	danielsh AT apache DOT org
Approved by:	bcr (mentor)
MFC after:	5 days
Differential Revision:	https://reviews.freebsd.org/D9313

usr.bin/find/find.1

@@ -31,7 +31,7 @@
 .\"	@(#)find.1	8.7 (Berkeley) 5/9/95
 .\" $FreeBSD$
 .\"
-.Dd April 13, 2014
+.Dd January 24, 2017
 .Dt FIND 1
 .Os
 .Sh NAME
@@ -572,6 +572,7 @@ processes all but the command line arguments.
 True if the difference between the file last modification time and the time
 .Nm
 was started, rounded up to the next full minute, is
+more than
 .Ar n
 .Pq + Ns Ar n ,
 less than