Fix detection of latex fragments

* org-element.el (org-element-latex-fragment-parser):
* org.el (org-latex-regexps): Fix the detection of latex
  fragments.  Uses syntax tables to detect whitespaces and punctuation
  marks following the final $ sign.

In order to qualify as a math delimiter, the final $ sign of a LaTeX
fragment has to be followed by a whitespace or punctuation mark but the
regexp used in the previous code matched only a small number of
punctuation marks and therefore missed some latex fragments.

doc/org.texi

@@ -10347,9 +10347,10 @@ Text within the usual @LaTeX{} math delimiters.  To avoid conflicts with
 currency specifications, single @samp{$} characters are only recognized as
 math delimiters if the enclosed text contains at most two line breaks, is
 directly attached to the @samp{$} characters with no whitespace in between,
-and if the closing @samp{$} is followed by whitespace, punctuation or a dash.
-For the other delimiters, there is no such restriction, so when in doubt, use
-@samp{\(...\)} as inline math delimiters.
+and if the closing @samp{$} is followed by whitespace or punctuation
+(parentheses and quotes are considered to be punctuation in this
+context).  For the other delimiters, there is no such restriction, so when in
+doubt, use @samp{\(...\)} as inline math delimiters.
 @end itemize
 
 @noindent For example:

lisp/org-element.el

@@ -2959,7 +2959,7 @@ Assume point is at the beginning of the LaTeX fragment."
 			 (search-forward "$" nil t 2)
 			 (not (memq (char-before (match-beginning 0))
 				    '(?\s ?\t ?\n ?, ?.)))
-			 (looking-at "\\([- \t.,?;:'\"]\\|$\\)")
+			 (looking-at "\\(\\s.\\|\\s-\\|\\s(\\|\\s)\\|\\s\"\\|$\\)")
 			 (point)))
 		(case (char-after (1+ (point)))
 		  (?\( (search-forward "\\)" nil t))

lisp/org.el

@@ -540,8 +540,8 @@ An entry can be toggled between COMMENT and normal with
   '(("begin" "^[ \t]*\\(\\\\begin{\\([a-zA-Z0-9\\*]+\\)[^\000]+?\\\\end{\\2}\\)" 1 t)
     ;; ("$" "\\([ 	(]\\|^\\)\\(\\(\\([$]\\)\\([^ 	\r\n,.$].*?\\(\n.*?\\)\\{0,5\\}[^ 	\r\n,.$]\\)\\4\\)\\)\\([ 	.,?;:'\")]\\|$\\)" 2 nil)
     ;; \000 in the following regex is needed for org-inside-LaTeX-fragment-p
-    ("$1" "\\([^$]\\|^\\)\\(\\$[^ 	\r\n,;.$]\\$\\)\\([- 	.,?;:'\")\000]\\|$\\)" 2 nil)
-    ("$" "\\([^$]\\|^\\)\\(\\(\\$\\([^ 	\r\n,;.$][^$\n\r]*?\\(\n[^$\n\r]*?\\)\\{0,2\\}[^ 	\r\n,.$]\\)\\$\\)\\)\\([- 	.,?;:'\")\000]\\|$\\)" 2 nil)
+    ("$1" "\\([^$]\\|^\\)\\(\\$[^ 	\r\n,;.$]\\$\\)\\(\\s.\\|\\s-\\|\\s(\\|\\s)\\|\\s\"\\|\000\\|$\\)" 2 nil)
+    ("$"  "\\([^$]\\|^\\)\\(\\(\\$\\([^ 	\r\n,;.$][^$\n\r]*?\\(\n[^$\n\r]*?\\)\\{0,2\\}[^ 	\r\n,.$]\\)\\$\\)\\)\\(\\s.\\|\\s-\\|\\s(\\|\\s)\\|\\s\"\\|\000\\|$\\)" 2 nil)
     ("\\(" "\\\\([^\000]*?\\\\)" 0 nil)
     ("\\[" "\\\\\\[[^\000]*?\\\\\\]" 0 nil)
     ("$$" "\\$\\$[^\000]*?\\$\\$" 0 nil))