jail.conf.5: minor cleanup (spdx, macros, xrefs)

+ expand see also section with other relevant pages and the handbook
+ tag paths with the path macro so they can be searched with apropos
+ tag spdx, one sentance per line

MFC after:	3 days

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1371

(cherry picked from commit 944c74b7d9)

usr.sbin/jail/jail.conf.5

@@ -1,3 +1,6 @@
+.\"-
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
 .\" Copyright (c) 2012 James Gritton
 .\" All rights reserved.
 .\"
@@ -22,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd September 5, 2023
+.Dd September 21, 2024
 .Dt JAIL.CONF 5
 .Os
 .Sh NAME
@@ -169,17 +172,17 @@ A line of the form
 .Pp
 will include another file (or files) in the configuration.
 The filename should be either absolute, or relative to the
-configuration file's directory.  It cannot contain variable
-expansions, but may contain
+configuration file's directory.
+It cannot contain variable expansions, but may contain
 .Xr glob 3
 patterns.
 .Pp
 The included file must exist, though a filename glob may match zero or
-more files.  This allows inclusion of any/all files in a directory,
-such as
-.Dq /etc/jail.conf.d/*.conf ,
+more files.
+This allows inclusion of any/all files in a directory, such as
+.Dq Pa /etc/jail.conf.d/*.conf ,
 or conditional inclusion of a single file, such as
-.Dq jail.foo[.]conf .
+.Dq Pa jail.foo[.]conf .
 .Ss Comments
 The configuration file may contain comments in the common C, C++, and
 shell formats:
@@ -238,10 +241,19 @@ bar {
 \[char46]include "/usr/local/etc/jail.*.conf";
 .Ed
 .Sh SEE ALSO
-.Xr jail_set 2 ,
+.Xr jail 2 ,
+.Xr jail 3 ,
+.Xr jail 3lua ,
 .Xr rc.conf 5 ,
 .Xr jail 8 ,
-.Xr jls 8
+.Xr jexec 8 ,
+.Xr jls 8 ,
+.Xr zfs-jail 8
+.Pp
+The
+.Dq Jails and Containers
+chapter of the
+.%B FreeBSD Handbook .
 .Sh HISTORY
 The
 .Xr jail 8