bug#73900: 30.0.91; auto-fill adds extra space in js-ts-mode

bug#73900: 30.0.91; auto-fill adds extra space in js-ts-mode

[Michael Kleehammer]

In Emacs 30, js-ts-mode auto-fill chooses an incorrect prefix when
wrapping comments.

1) emacs -Q 

2) In the scratch buffer:
   a) M-x js-ts-mode
   b) M-x auto-fill-mode
   c) M-x erase-buffer
   
3) Paste in a long JS comment:

   // This buffer is for text that is not saved, and for Lisp evaluation.  To create a file, visit it

4) At end of line, press <Space>.

The text wraps like so:

   // This buffer is for text that is not saved, and for Lisp evaluation.
   //   To create a file, visit it 

In previous versions, it would wrap like so:

   // This buffer is for text that is not saved, and for Lisp evaluation.
   // To create a file, visit it 


Thanks,
Michael Kleehammer

In GNU Emacs 30.0.91 (build 3, x86_64-pc-linux-gnu, GTK+ Version
 3.24.33, cairo version 1.16.0) of 2024-10-14 built on pangolin
Repository revision: b87fda63dd4a29c3c28e235904405f2d6709239e
Repository branch: emacs-30
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Pop!_OS 22.04 LTS

Configured using:
 'configure --with-tree-sitter --without-compress-install
 --without-mailutils 'CFLAGS=-O2 -march=native''

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG
LIBSELINUX LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER
PNG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER
X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: JavaScript

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
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  minibuffer-regexp-mode: t
  line-number-mode: t
  auto-fill-function: do-auto-fill
  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 compile comint ansi-osc ansi-color ring comp-run
comp-common rx 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 cl-seq js
c-ts-common treesit json subr-x map byte-opt gv bytecomp byte-compile
imenu cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs cl-loaddefs cl-lib rmc iso-transl tooltip
cconv eldoc paren electric uniquify ediff-hook vc-hooks lisp-float-type
elisp-mode mwheel term/x-win x-win term/common-win x-dnd touch-screen
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 dbusbind
inotify dynamic-setting system-font-setting font-render-setting cairo
gtk x-toolkit xinput2 x multi-tty move-toolbar make-network-process
native-compile emacs)

Memory information:
((conses 16 112390 11199) (symbols 48 9369 0) (strings 32 27327 1317)
 (string-bytes 1 999282) (vectors 16 15439)
 (vector-slots 8 200959 7612) (floats 8 28 7) (intervals 56 277 0)
 (buffers 992 11))