sed.1: Adjust examples to fit in one line + SPDX

Examples were previously overflowing at MANWIDTH 80. Keep the same
complexity but use shorter phrases to make them easier to read. Tag
SPDX while here.

MFC after:		3 days
Reviewed by:		bcr
Discussed with:		emaste
Differential Revision:	https://reviews.freebsd.org/D50867

usr.bin/sed/sed.1

@@ -1,3 +1,6 @@
+.\"
+.\" SPDX-License-Identifier: BSD-3-Clause
+.\"
 .\" Copyright (c) 1992, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
@@ -28,7 +31,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd December 17, 2024
+.Dd June 14, 2025
 .Dt SED 1
 .Os
 .Sh NAME
@@ -597,17 +600,17 @@ with
 .Ql baz
 when piped from another command:
 .Bd -literal -offset indent
-echo "An alternate word, like bar, is sometimes used in examples." | sed 's/bar/baz/'
+echo "use bar in examples" | sed 's/bar/baz/'
 .Ed
 .Pp
 Using backlashes can sometimes be hard to read and follow:
 .Bd -literal -offset indent
-echo "/home/example" | sed  's/\\/home\\/example/\\/usr\\/local\\/example/'
+echo "/bin/bash" | sed 's/\\/bin\\/bash/\\/bin\\/sh/'
 .Ed
 .Pp
 Using a different separator can be handy when working with paths:
 .Bd -literal -offset indent
-echo "/home/example" | sed 's#/home/example#/usr/local/example#'
+echo "/bin/bash" | sed 's#/bin/bash#/bin/sh#'
 .Ed
 .Pp
 Replace all occurrences of