bug#37296: \left breaks syntax highlighting

[Hendrik Rommeswinkel]

Using \left(\right) without a space before \left( breaks the syntax
highlighting. The remainder of the document is shown in yellow but
sometimes editing b e l o w the \left(\right) will make syntax
highlighting work again. A second issue with \left(\right) is that
typing "\left(" produces "\left(()\right)" instead of "\left(\right)".

Many thanks for your efforts on auctex!

Emacs  : GNU Emacs 26.2 (build 1, x86_64-w64-mingw32)
 of 2019-04-13
Package: 12.1.2

current state:
==============
(setq
 AUCTeX-date "2019-02-08"
 window-system 'w32
 LaTeX-version "2e"
 TeX-style-path '("~/.emacs.d/auctex"
"c:/Users/user/AppData/Roaming/.emacs.d/elpa/auctex-12.1.2/style" 
"c:/Users/user/AppData/Roaming/.emacs.d/auctex/auto" 
"c:/Users/user/AppData/Roaming/.emacs.d/auctex/style" "auto" "style")
 TeX-auto-save t
 TeX-parse-self t
 TeX-master t
 TeX-command-list '(("LatexMk" "latexmk %(-PDF)%S%(mode) 
%(file-line-error) %(extraopts) %t"
                     TeX-run-latexmk nil (plain-tex-mode latex-mode 
doctex-mode) :help
                     "Run LatexMk")
                    ("TeX"
                     "%(PDF)%(tex) %(file-line-error) %`%(extraopts) 
%S%(PDFout)%(mode)%' %t"
                     TeX-run-TeX nil (plain-tex-mode ams-tex-mode 
texinfo-mode) :help
                     "Run plain TeX")
                    ("LaTeX" "%`%l%(mode)%' %T" TeX-run-TeX nil 
(latex-mode doctex-mode)
                     :help "Run LaTeX")
                    ("Makeinfo" "makeinfo %(extraopts) %t" 
TeX-run-compile nil
                     (texinfo-mode) :help "Run Makeinfo with Info output")
                    ("Makeinfo HTML" "makeinfo %(extraopts) --html %t" 
TeX-run-compile nil
                     (texinfo-mode) :help "Run Makeinfo with HTML output")
                    ("AmSTeX" "amstex %(PDFout) %`%(extraopts) 
%S%(mode)%' %t" TeX-run-TeX
                     nil (ams-tex-mode) :help "Run AMSTeX")
                    ("ConTeXt" "%(cntxcom) --once --texutil 
%(extraopts) %(execopts)%t"
                     TeX-run-TeX nil (context-mode) :help "Run ConTeXt 
once")
                    ("ConTeXt Full" "%(cntxcom) %(extraopts) 
%(execopts)%t" TeX-run-TeX nil
                     (context-mode) :help "Run ConTeXt until completion")
                    ("BibTeX" "bibtex %s" TeX-run-BibTeX nil t :help 
"Run BibTeX")
                    ("Biber" "biber %s" TeX-run-Biber nil t :help "Run 
Biber")
                    ("View" "%V" TeX-run-discard-or-function t t :help 
"Run Viewer")
                    ("Print" "%p" TeX-run-command t t :help "Print the 
file")
                    ("Queue" "%q" TeX-run-background nil t :help "View 
the printer queue"
                     :visible TeX-queue-command)
                    ("File" "%(o?)dvips %d -o %f " TeX-run-dvips t t :help
                     "Generate PostScript file")
                    ("Dvips" "%(o?)dvips %d -o %f " TeX-run-dvips nil t 
:help
                     "Convert DVI file to PostScript")
                    ("Dvipdfmx" "dvipdfmx %d" TeX-run-dvipdfmx nil t :help
                     "Convert DVI file to PDF with dvipdfmx")
                    ("Ps2pdf" "ps2pdf %f" TeX-run-ps2pdf nil t :help
                     "Convert PostScript file to PDF")
                    ("Glossaries" "makeglossaries %s" TeX-run-command 
nil t :help
                     "Run makeglossaries to create glossary file")
                    ("Index" "makeindex %s" TeX-run-index nil t :help
                     "Run makeindex to create index file")
                    ("upMendex" "upmendex %s" TeX-run-index t t :help
                     "Run upmendex to create index file")
                    ("Xindy" "texindy %s" TeX-run-command nil t :help
                     "Run xindy to create index file")
                    ("Check" "lacheck %s" TeX-run-compile nil 
(latex-mode) :help
                     "Check LaTeX file for correctness")
                    ("ChkTeX" "chktex -v6 %s" TeX-run-compile nil 
(latex-mode) :help
                     "Check LaTeX file for common mistakes")
                    ("Spell" "(TeX-ispell-document \"\")" 
TeX-run-function nil t :help
                     "Spell-check the document")
                    ("Clean" "TeX-clean" TeX-run-function nil t :help
                     "Delete generated intermediate files")
                    ("Clean All" "(TeX-clean t)" TeX-run-function nil t 
:help
                     "Delete generated intermediate and output files")
                    ("Other" "" TeX-run-command t t :help "Run an 
arbitrary command"))
 )