Fix broken links (#105)

* Fix broken links

Fix broken link from `on-stack-dyn-dispatch.md` to `dtor-finally.md`.
Link to `RAII.md` was broken as well.

idioms/on-stack-dyn-dispatch.md

@@ -74,8 +74,8 @@ Read`
 
 ## See also
 
-* [Finalisation in destructors](idioms/dtor-finally.md) and 
-[RAII guards](patterns/RAII.md) can benefit from tight control over lifetimes.
+* [Finalisation in destructors](dtor-finally.md) and 
+[RAII guards](../patterns/RAII.md) can benefit from tight control over lifetimes.
 * For conditionally filled `Option<&T>`s of (mutable) references, one can
 initialize an `Option<T>` directly and use its [`.as_ref()`] method to get an
 optional reference.