bug#39277: 26.3; Tcl font lock does not understand quoting

[Hadrien Lacour]

Hello, tcl-mode's font lock (highlighting) chokes on this simple case:
    puts {"hello}
where it considers the double quote inside the curly braces as a
"quoting" character.
I have confirmed it works with `emacs -Q`.


In GNU Emacs 26.3 (build 1, x86_64-pc-linux-gnu, X toolkit)
 of 2019-09-23 built on gentoo-zen2700x
Windowing system distributor 'The X.Org Foundation', version 11.0.12006000
System Description:     Gentoo Base System release 2.6

Recent messages:
Applying X config
For information about GNU Emacs and the GNU system, type C-h C-a.
Making completion list...

Configured using:
 'configure --prefix=/usr --build=x86_64-pc-linux-gnu
 --host=x86_64-pc-linux-gnu --mandir=/usr/share/man
 --infodir=/usr/share/info --datadir=/usr/share --sysconfdir=/etc
 --localstatedir=/var/lib --disable-silent-rules
 --docdir=/usr/share/doc/emacs-26.3-r1
 --htmldir=/usr/share/doc/emacs-26.3-r1/html --libdir=/usr/lib64
 --program-suffix=-emacs-26 --includedir=/usr/include/emacs-26
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 --with-x-toolkit=lucid --without-xaw3d 'CFLAGS=-march=native -pipe -O2'
 CPPFLAGS= 'LDFLAGS=-Wl,-O1 -Wl,--as-needed''

Configured features:
XPM NOTIFY ACL GNUTLS FREETYPE XFT ZLIB LUCID X11 XDBE XIM THREADS

Important settings:
  value of $LANG: en_US.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
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  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
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  auto-composition-mode: t
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  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  hs-minor-mode: t

Load-path shadows:
/home/hadrien/.emacs.d/elpa/flymake-1.0.8/flymake hides 
/usr/share/emacs/26.3/lisp/progmodes/flymake

Features:
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select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
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Memory information:
((conses 16 341610 9384)
 (symbols 48 32614 9)
 (miscs 40 93 178)
 (strings 32 113853 2521)
 (string-bytes 1 2844540)
 (vectors 16 33288)
 (vector-slots 8 769217 11356)
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 (intervals 56 333 0)
 (buffers 992 12))