Fix indentation
Fix &OPTIONAL + &REST handling in FIND-OPTIONAL-DISPATCH-TYPES

Previously, certain combinations of proclamations and definitions, such as

  (declaim (ftype (function (symbol &optional t &rest t)) foo))
  (defun foo (x &optional y &rest z))

lead to bogus STYLE-WARNINGs about mismatches between proclamation and
definition:

  The definition has one optional arg, but proclamation has zero.

This was caused by the simplifications of function types

     (function (symbol &optional t &rest t) symbol)
  ~> (function (symbol &rest t) symbol)

which FIND-OPTIONAL-DISPATCH-TYPES did not take into account.