bug#74844: 29.4; m-buffer: Broken Top Directory node in Info manual due to malformed Texinfo direntry

[Suhail Singh <suhailsingh247@gmail.com>]

The Texinfo entry in the "dir" and "m-buffer-doc.info" files are
malformed.  As a consequence the font-locking as well as the completion
for the Info-menu command are broken in the Top directory.  CC-ing
Stefan given his familiarity with documentation generation for the ELPA
package in question (based on git commits).

The @direntry for Texinfo is of the form ‘* DIRNAME: NODE.’ where ‘NODE’
is usually just ‘(FILENAME)’.  In the case of m-buffer it ought to be
something like "* m-buffer: (m-buffer-doc)."  However, the @direntry as
noted in the "dir" and "m-buffer-doc.info" files is "* m-buffer.doc."
As a result, `Info-follow-nearest-node' (bound to RET in Info-mode-map)
is unable to determine the appropriate node when point is on the
m-buffer-doc entry.  Digging deeper, the failure is due to the following
code resulting in nil:

#+begin_src emacs-lisp
  (Info-get-token (point) "\\* +" "\\* +\\(.*\\): ")
#+end_src

Fixing the direntry in the "dir" and "m-buffer-doc-info" files resolves
the issue.

Given that the documentation is generated from m-buffer-doc.org via
ox-texinfo, presumably the issue lies in the incorrect usage of the
obsolete TEXINFO_DIR_TITLE keyword.  Presumably the fix would be to use
the TEXINFO_FILENAME and, possibly, the TEXINFO_DIR_NAME keywords.
However, for some reason I am unable to generate the documentation
locally.  As such I am not submitting a patch.  Hope this helps.

In GNU Emacs 29.4 (build 2, x86_64-suse-linux-gnu, GTK+ Version 3.24.43,
cairo version 1.18.2)
System Description: openSUSE Tumbleweed

Configured using:
 'configure --disable-build-details --without-pop --with-mailutils
 --with-native-compilation --without-hesiod --with-gameuser=:games
 --with-kerberos --with-kerberos5 --with-file-notification=inotify
 --with-modules --enable-autodepend --prefix=/usr
 --mandir=/usr/share/man --infodir=/usr/share/info --datadir=/usr/share
 --localstatedir=/var --sharedstatedir=/var/lib
 --libexecdir=/usr/libexec --with-file-notification=yes
 --libdir=/usr/lib64
 --enable-locallisppath=/usr/share/emacs/29.4/site-lisp:/usr/share/emacs/site-lisp
 --with-x --with-xim --with-sound --with-xpm --with-jpeg --with-tiff
 --with-gif --with-png --with-rsvg --with-dbus --with-webp --with-xft
 --with-imagemagick --without-gpm --with-x-toolkit=gtk3 --with-pgtk
 --with-toolkit-scroll-bars --x-includes=/usr/include
 --x-libraries=/usr/lib64 --with-libotf --with-m17n-flt --with-cairo
 --with-xwidgets --build=x86_64-suse-linux --with-dumping=pdumper
 'CFLAGS=-O2 -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3
 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables
 -fstack-clash-protection -Werror=return-type -flto=auto -g
 -D_GNU_SOURCE -DGDK_DISABLE_DEPRECATION_WARNINGS
 -DGLIB_DISABLE_DEPRECATION_WARNINGS -pipe -Wno-pointer-sign
 -Wno-unused-variable -Wno-unused-label -fno-optimize-sibling-calls
 -DPDMP_BASE='\''"emacs-wayland"'\''' LDFLAGS=-Wl,-O2'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ
IMAGEMAGICK JPEG JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PGTK PNG RSVG SECCOMP SOUND SQLITE3
THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XIM XWIDGETS GTK3 ZLIB

Important settings:
  value of $LC_NUMERIC: POSIX
  value of $LC_TIME: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Info

Minor modes in effect:
  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
  isearch-fold-quotes-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  buffer-read-only: 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:
None found.

Features:
(shadow sort mail-extr info emacsbug message mailcap yank-media puny
dired dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg
rfc6068 epg-config gnus-util text-property-search time-date mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils comp
comp-cstr warnings icons subr-x rx cl-seq cl-macs gv cl-extra help-mode
cl-loaddefs cl-lib bytecomp byte-compile ispell rmc delsel lpr
easy-mmode pcase iso-transl tooltip cconv eldoc paren electric uniquify
ediff-hook vc-hooks lisp-float-type elisp-mode mwheel term/pgtk-win
pgtk-win term/common-win pgtk-dnd 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 seq simple cl-generic indonesian philippine
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 theme-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 xwidget-internal dbusbind inotify dynamic-setting
system-font-setting font-render-setting cairo gtk pgtk lcms2 multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 101816 9593)
 (symbols 48 7600 0)
 (strings 32 23316 1856)
 (string-bytes 1 792835)
 (vectors 16 16145)
 (vector-slots 8 336083 17636)
 (floats 8 31 20)
 (intervals 56 4892 0)
 (buffers 984 12))