bug#54789: 29.0.50; csv-mode off by one error?

[Johann Höchtl]

When opening a CSV file, the field number in the modeline is initially
displayed as 'F0', if I move point past the first character it get's
updated to F1. This behaviour repeats for every other field in the csv
file. So If I am in the buffer at the frist character of field 5 it is
still reported as F4, if imove to the second character of field 5
it is correctly reported as F5.

In GNU Emacs 29.0.50 (build 1, x86_64-w64-mingw32)
Repository revision: c5af19cba5924de89a38e7a177c07f42fd3cd543
Repository branch: master
Windowing system distributor 'Microsoft Corp.', version 10.0.18363
System Description: Microsoft Windows 10 Enterprise (v10.0.1909.18363.2158)

Configured using:
 'configure --prefix=/d/a/emacs-build/emacs-build/pkg/master-x86_64
 'CFLAGS=-Ofast -fno-finite-math-only' --with-native-compilation
 --with-zlib --with-gnutls --with-xml2 --with-lcms2 --with-json
 --with-harfbuzz --without-cairo --with-rsvg --with-png --with-gif
 --without-tiff --with-jpeg --with-xpm --disable-build-details
 --without-dbus --without-compress-install'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS
TOOLKIT_SCROLL_BARS WEBP XPM ZLIB

Important settings:
  value of $LC_ALL: en_US.utf8
  value of $LANG: C
  locale-coding-system: cp1252

Major mode: CSV

Minor modes in effect:
  csv-field-index-mode: t
  shell-dirtrack-mode: t
  windmove-mode: t
  savehist-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
c:/Users/HoechtlJ/WorkFolders/Documents/.emacs.d/elpa/transient-20220406.1156/transient hides c:/Users/HoechtlJ/AppData/Local/Emacs/share/emacs/29.0.50/lisp/transient

Features:
(shadow mail-extr emacsbug comp comp-cstr warnings message yank-media
puny rfc822 mml mml-sec epa derived epg rfc6068 epg-config gnus-util
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils csv-mode sort rmc sql view mule-util cal-move parse-time org
ob ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-footnote
org-src ob-comint org-pcomplete org-list org-faces org-entities
org-version ob-emacs-lisp ob-core ob-eval org-table oc-basic bibtex
iso8601 ol org-keys oc org-compat advice org-macs org-loaddefs
format-spec find-func cal-menu calendar cal-loaddefs cl-extra help-mode
find-dired ffap shell pcomplete files-x grep compile
text-property-search comint ansi-color company-oddmuse company-keywords
company-etags etags fileloop generator xref project ring company-gtags
company-dabbrev-code company-dabbrev company-files company-clang
company-capf company-cmake company-semantic company-template
company-bbdb company pcase refill flyspell ispell markdown-mode rx color
thingatpt noutline outline misearch multi-isearch time-date dired-aux
dired dired-loaddefs deeper-blue-theme windmove savehist cus-load
pasteex-mode easy-mmode finder-inf info package browse-url url url-proxy
url-privacy url-expand url-methods url-history url-cookie url-domsuf
url-util mailcap url-handlers url-parse auth-source cl-seq eieio
eieio-core cl-macs eieio-loaddefs password-cache json map url-vars seq
gv subr-x byte-opt bytecomp byte-compile cconv cl-loaddefs cl-lib
iso-transl tooltip eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode mwheel dos-w32 ls-lisp disp-table
term/w32-win w32-win w32-vars term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer nadvice simple cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese composite emoji-zwj charscript charprop
case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads
w32notify w32 lcms2 multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 434980 18141)
 (symbols 48 24689 1)
 (strings 32 123187 4936)
 (string-bytes 1 3562828)
 (vectors 16 48098)
 (vector-slots 8 1612874 86964)
 (floats 8 236 368)
 (intervals 56 6687 379)
 (buffers 992 20))