ports.7/FILES: Expand and refactor into 3 tables

Add make.conf, CHANGES, CONTRIBUTING.Md, UPDATING, and Tools/scripts.
Refactor the FILES section of the ports reference manual into a bigger
table with three sections separated by root directory. Remove preceeding
article from all but "the big Kahuna", and root dirs where reasonable.

MFC after:              3 days
Relnotes:		yes
Reported by:            adamw, arrowd, linimon
Differential Revision:	https://reviews.freebsd.org/D55441

share/man/man7/ports.7

@@ -25,7 +25,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd February 21, 2026
+.Dd February 24, 2026
 .Dt PORTS 7
 .Os
 .Sh NAME
@@ -596,30 +596,41 @@ Which directory to use for the
 data.
 .El
 .Sh FILES
-.Bl -tag -width "/usr/ports/Mk/bsd.port.mk" -compact
-.It Pa /usr/ports/
-The default ports directory.
-.It Pa /usr/ports/Mk/bsd.port.mk
-The big Kahuna.
-.It Pa /var/db/ports/
-The directory where the results of configuring
-.Va OPTIONS
-are stored.
+.Bl -tag -width "ports/CONTRIBUTING.md" -compact
+.It Pa ports/CHANGES
+BREAKING NEWS to read before creating ports!
+.It Pa ports/CONTRIBUTING.md
+Instructions for contributing to the ports tree.
+.It Pa ports/Mk/bsd.port.mk
+The inner workings of the ports framework.
+.It Pa ports/Tools/scripts/
+Grab bag of tools for maintaining ports.
+.It Pa ports/UPDATING
+BREAKING NEWS to read before upgrading ports!
+.It Pa ports/distfiles/
+Directory where fetched files are stored.
+.Pp
 .It Pa ${PORT}/Makefile
-The specification for building the port.
-.It Pa ${PORT}/distfiles
-The directory where fetched files are stored.
+Specification for building the port.
 .It Pa ${PORT}/distinfo
-The checksums generated with
+Checksums generated with
 .Ql make makesum .
 .It Pa ${PORT}/files/
-The directory for any patches.
+Directory for patches or any additional files.
 .It Pa ${PORT}/pkg-descr
-The long description of the port.
+Long description of the port.
 .It Pa ${PORT}/pkg-plist
-The list of all files installed by the port.
-.It Pa ${PORT}/work
+List of all files installed by the port.
+.It Pa ${PORT}/work/
 The port's building and staging directory.
+.Pp
+.It Pa /etc/make.conf
+Settings for the port-building framework.
+.It Pa /usr/ports/
+Canonical ports tree location.
+.It Pa /var/db/ports/
+Directory for storing configured
+.Va OPTIONS .
 .El
 .Sh EXAMPLES
 .Bl -tag -width 0n