bug#34131: File Variable doc: Remove the quotes on "variable"

[積丹尼 Dan Jacobson]

In (info "(emacs) Safe File Variables")

   File-local variables can be dangerous; when you visit someone else’s
   file, there’s no telling what its local variables list could do to your
   Emacs.  Improper values of the ‘eval’ “variable”, and other variables

                                            ^        ^ please remove the
                                            quotes on “variable”.

   such as ‘load-path’, could execute Lisp code you didn’t intend to run.

(Or is there really is a variable variable, link something to it.)