org.texi (Orgstruct mode): Fix suggested setting of `orgstruct-heading-prefix-regexp'

* org.texi (Orgstruct mode): Fix suggested setting of
`orgstruct-heading-prefix-regexp'.

Thanks to Nathaniel Cunningham for reporting this.
http://mid.gmane.org/CAAGwS84TrrmPdO9eQLc1acCvwTiPy=N5TnC1p2S-dz5jazDgjg%40mail.gmail.com

doc/org.texi

@@ -2041,7 +2041,7 @@ line of an item.
 You can also use Org structure editing to fold and unfold headlines in
 @emph{any} file, provided you defined @code{orgstruct-heading-prefix-regexp}:
 the regular expression must match the local prefix to use before Org's
-headlines.  For example, if you set this variable to @code{"^;; "} in Emacs
+headlines.  For example, if you set this variable to @code{";; "} in Emacs
 Lisp files, you will be able to fold and unfold headlines in Emacs Lisp
 commented lines.  Some commands like @code{org-demote} are disabled when the
 prefix is set, but folding/unfolding will work correctly.