org.el (org-mode): Set the syntax of the " character to "string quote"

* org.el (org-mode): Set the syntax of the " character to
"string quote".

Thanks to Samuel Wales for asking a related question and to Nick Dokos
for suggesting this solution.

lisp/org.el

@@ -5074,6 +5074,7 @@ The following commands are available:
   ;; Calc embedded
   (org-set-local 'calc-embedded-open-mode "# ")
   (modify-syntax-entry ?@ "w")
+  (modify-syntax-entry ?\" "\"")
   (if org-startup-truncated (setq truncate-lines t))
   (org-set-local 'font-lock-unfontify-region-function
 		 'org-unfontify-region)