Enable kernel reproducible builds on stable branch

When the stable/13 branch was created the userland knob (in
share/mk/src.opts.mk) was changed to default to yes, but the kernel
default was not changed.  These two should always have the same default.
Regenerate src.conf.5, as the differing defaults previously confused
`makeman`.

Fixes: bfd1570515 ("Create the stable/13 branch")
Sponsored by: The FreeBSD Foundation
MFS from:	stable/13
MFS to:		releng/14.1

(cherry picked from commit d8644a5d2458588dd7d8e44bd23c6cacaead19b7)

share/man/man5/src.conf.5

@@ -1506,10 +1506,10 @@ Do not apply the Relocation Read-Only (RELRO) vulnerability mitigation.
 See also the
 .Va BIND_NOW
 option.
-.It Va WITH_REPRODUCIBLE_BUILD
-Exclude build metadata (such as the build time, user, or host)
-from the kernel, boot loaders, and uname output, so that builds produce
-bit-for-bit identical output.
+.It Va WITHOUT_REPRODUCIBLE_BUILD
+Include build metadata (such as the build time, user, and host)
+in the kernel, boot loaders, and uname output.
+Successive builds will not be bit-for-bit identical.
 .It Va WITHOUT_RESCUE
 Do not build
 .Xr rescue 8 .

sys/conf/kern.opts.mk

@@ -46,6 +46,7 @@ __DEFAULT_YES_OPTIONS = \
     NETGRAPH \
     OFED \
     PF \
+    REPRODUCIBLE_BUILD \
     SCTP_SUPPORT \
     SOURCELESS_HOST \
     SOURCELESS_UCODE \
@@ -60,7 +61,6 @@ __DEFAULT_NO_OPTIONS = \
     INIT_ALL_ZERO \
     KERNEL_RETPOLINE \
     RATELIMIT \
-    REPRODUCIBLE_BUILD \
     VERIEXEC
 
 # Some options are totally broken on some architectures. We disable