lock.1: align options + tag spdx

Reviewed by:	imp, mhorne
MFC after:	3 days
Pull Request:	https://github.com/freebsd/freebsd-src/pull/1522

usr.bin/lock/lock.1

@@ -1,3 +1,6 @@
+.\"-
+.\" SPDX-License-Identifier: BSD-3-Clause
+.\"
 .\" Copyright (c) 1987, 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
@@ -46,7 +49,7 @@ will timeout after some interval of time and it may be killed by someone
 with the appropriate permission.
 .Pp
 The following options are available:
-.Bl -tag -width indent
+.Bl -tag -width "-t timeout"
 .It Fl n
 Do not use a timeout value.
 Terminal will be locked forever.