Prepare for 0.23 release.

Prepare for 0.23 release.

* gettext-runtime/doc/matrix.texi: Update from TP.
* gettext-runtime/doc/nls.texi (STATUS): Update.
* gettext-runtime/po/Makefile.in.in: Bump Origin version and
GETTEXT_MACRO_VERSION.
* gettext-runtime/m4/po.m4 (AM_PO_SUBDIRS): Bump GETTEXT_MACRO_VERSION
accordingly.
* gettext-runtime/m4/gettext.m4: Update comments.
* gettext-runtime/intl/libgnuintl.in.h (LIBINTL_VERSION): Bump.
* libtextstyle/version.sh: Update VERSION_NUMBER, RELEASE_DATE.
* gettext-tools/libgettextpo/gettext-po.in.h (LIBGETTEXTPO_VERSION): Bump.
* gettext-runtime/intl/Makefile.am (LTV_*): Bump to 12:1:4.
* libtextstyle/lib/Makefile.am (LTV_*): Bump to 2:2:2.
* gettext-tools/libgettextpo/Makefile.am (LTV_*): Bump to 5:11:5.
* gettext-runtime/src/envsubst.c (main): Update copyright year in --version
output.
* gettext-runtime/src/gettext.c (main): Likewise.
* gettext-runtime/src/gettext.sh.in (func_version): Likewise.
* gettext-runtime/src/ngettext.c (main): Likewise.
* gettext-tools/src/cldr-plurals.c (main): Likewise.
* gettext-tools/src/hostname.c (main): Likewise.
* gettext-tools/src/msgattrib.c (main): Likewise.
* gettext-tools/src/msgcat.c (main): Likewise.
* gettext-tools/src/msgcmp.c (main): Likewise.
* gettext-tools/src/msgcomm.c (main): Likewise.
* gettext-tools/src/msgconv.c (main): Likewise.
* gettext-tools/src/msgen.c (main): Likewise.
* gettext-tools/src/msgexec.c (main): Likewise.
* gettext-tools/src/msgfilter.c (main): Likewise.
* gettext-tools/src/msgfmt.c (main): Likewise.
* gettext-tools/src/msggrep.c (main): Likewise.
* gettext-tools/src/msginit.c (main): Likewise.
* gettext-tools/src/msgmerge.c (main): Likewise.
* gettext-tools/src/msgunfmt.c (main): Likewise.
* gettext-tools/src/msguniq.c (main): Likewise.
* gettext-tools/src/recode-sr-latin.c (main): Likewise.
* gettext-tools/src/urlget.c (main): Likewise.
* gettext-tools/src/xgettext.c (main): Likewise.
* gettext-tools/misc/convert-archive.in (func_version): Likewise.
* gettext-tools/misc/gettextize.in (func_version): Likewise.
* gettext-tools/misc/autopoint.in: Likewise. Accept version 0.23.
* gettext-tools/configure.ac (ARCHIVE_VERSION): Bump to 0.23.
* NEWS, gettext-runtime/NEWS: Update.