release(7): Remove stray references to DOC* variables

We now live in the world of git, and release(7) should reflect that.

As of the commit referenced below, release images also no longer
include (stale) documentation, as the documentation has moved to
AsciiDoctor. This means that a few environment variables no longer
make sense, so remove them from their sections and mention them in
the compatibility section instead.

While here, also pet mandoc.

PR: 253615
MFC after: 3 days
MFC with: f61e92ca5a release: permanently remove the 'reldoc'
target and associates

Reviewed by:	gjb, lwhsu, yuripv
Differential Revision:	https://reviews.freebsd.org/D28881

share/man/man7/release.7

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 1, 2020
+.Dd February 23, 2021
 .Dt RELEASE 7
 .Os
 .Sh NAME
@@ -143,24 +143,18 @@ Additional
 .Xr make 1
 arguments to pass through, which directly affect the
 tuning of the build chroot.
-.It Va SVNROOT
+.It Va GITROOT
 The
-.Xr svn 1
+.Xr git 1
 host used to check out the various trees.
 Defaults to
-.Pa svn://svn.FreeeBSD.org .
+.Pa https://git.FreeeBSD.org .
 .It Va SRCBRANCH
 The
 .Li src/
 branch to use.
 Defaults to
-.Va head/@rHEAD .
+.Fl b Va main .
-.It Va DOCBRANCH
-The
-.Li doc/
-branch to use.
-Defaults to
-.Va head/@rHEAD .
 .It Va PORTBRANCH
 The
 .Li ports/
@@ -226,15 +220,6 @@ Defaults to setting the number of
 jobs
 .Pq Ar -j
 to half the number of CPUs available on a SMP-capable system.
-.It Va NODOC
-Set to a non-empty value to skip the
-.Li doc/
-tree checkout.
-When set,
-.Va NODOC
-will prevent the
-.Fa doc.txz
-distribution package from being created.
 .It Va NOPORTS
 Set to a non-empty value to skip the
 .Li ports/
@@ -244,8 +229,6 @@ When set,
 will prevent the
 .Fa ports.txz
 distribution package from being created.
-Setting this also sets
-.Va NODOC .
 .It Va WITH_DVD
 Set to a non-empty value to include the
 .Cm dvdrom
@@ -268,7 +251,7 @@ which uses all available cores on the system.
 .It Va VCSCMD
 The command run to obtain the source trees.
 Defaults to
-.Qq Cm svn checkout .
+.Qq Cm git clone Fl q .
 .It Va CHROOTBUILD_SKIP
 If defined, the
 .Li buildworld ,
@@ -289,14 +272,6 @@ within the
 This is intended for use only when
 .Fa /usr/src
 is expected to exist by alternative means.
-.It Va DOC_UPDATE_SKIP
-Set to a non-empty value to prevent checkout or update of
-.Fa /usr/doc
-within the
-.Xr chroot 8 .
-This is intended for use only when
-.Fa /usr/doc
-is expected to exist by alternative means.
 .It Va PORTS_UPDATE_SKIP
 Set to a non-empty value to prevent checkout or update of
 .Fa /usr/ports
@@ -317,9 +292,7 @@ release builds.
 .Pp
 When set,
 .Va WITH_DVD
-is unset, and
+is unset.
-.Va NODOC
-is defined.
 Additionally,
 .Va EMBEDDED_TARGET
 and
@@ -587,27 +560,10 @@ Location of a directory containing the ports tree.
 By default,
 .Pa /usr/ports .
 If it is unset or cannot be found, ports will not be included in the release.
-.It Ev DOCDIR
-Location of a directory containing the doc tree.
-By default,
-.Pa /usr/doc .
-If it is unset or cannot be found, most documentation will not be included in
-the release; see
-.Ev NODOC
-below.
 .It Ev NOPORTS
 If defined, the Ports Collection will be omitted from the release.
 .It Ev NOSRC
 If set, do not include system source code in the release.
-.It Ev NODOC
-If defined, the XML-based documentation from the
-.Fx
-Documentation Project will not be built.
-However, the
-.Dq doc
-distribution will still be created with the minimal documentation set
-provided in
-.Pa src/share/doc .
 .It Ev TARGET
 The target hardware platform.
 This is analogous to the
@@ -657,7 +613,7 @@ The following sequence of commands can be used to build a
 .Dq "-CURRENT snapshot":
 .Bd -literal -offset indent
 cd /usr
-svn co svn://svn.freebsd.org/base/head src
+git clone https://git.freebsd.org/src.git src
 cd src
 make buildworld buildkernel
 cd release
@@ -714,11 +670,19 @@ The target directory can be changed by specifying the
 .Va CHROOTDIR
 variable in
 .Li release.conf .
+.Sh COMPATIBILITY
+The reldoc target was removed in commit f61e92ca5a23, and
+.Ev DOCDIR ,
+.Ev DOCBRANCH ,
+.Ev DOC_UPDATE_SKIP ,
+and
+.Ev NODOC
+are therefore no longer supported.
 .Sh SEE ALSO
 .Xr cc 1 ,
+.Xr git 1 Pq Pa ports/devel/git ,
 .Xr install 1 ,
 .Xr make 1 ,
-.Xr svn 1 Pq Pa ports/devel/subversion ,
 .Xr uname 1 ,
 .Xr md 4 ,
 .Xr make.conf 5 ,
@@ -771,7 +735,7 @@ is heavily based on the
 script.
 .Pp
 At near 1000 revisions spread over multiple branches, the
-.Xr svn 1
+.Xr git 1
 log of
 .Pa src/release/Makefile
 contains a vivid historical record of some