Fix typo declaratoins

Author: sorear

S12-objects.pod

@@ -995,7 +995,7 @@ not governed within that same file by a C<proto> of the same short
 name, it is considered unique, an I<only> sub.  (An imported C<proto>
 can function as such a governing declaration.)
 
-For method declaratoins, the C<proto>, C<multi>, and C<only>
+For method declarations, the C<proto>, C<multi>, and C<only>
 declarations work similarly but not identically.  The explicit
 declarations work the same, except that calculation of of governance
 and candidate sets proceeds via the inheritance tree rather than via