Merge bitcoin/bitcoin#28556: doc: fix link to developer-notes.md file in multiprocess.md

d9b172c doc: fix link to developer-notes.md file in multiprocess.md (David Álvarez Rosa)

Pull request description:

  Fix link to `developer-notes.md` file in `multiprocess.md`.

ACKs for top commit:
  fanquake:
    ACK d9b172c

Tree-SHA512: 55fffefb37c4d67acb1fa8b0660216ec1c7f2c2314d11e4d319cae40480ed59ef448909fa2ca334167c86d60d41932220dce4186e28fa300f4d03eb0b3c769d0

Author: fanquake

doc/design/multiprocess.md

@@ -38,7 +38,7 @@ Alternately, you can install [Cap'n Proto](https://capnproto.org/) and [libmulti
 
 Cross process Node, Wallet, and Chain interfaces are defined in
 [`src/interfaces/`](../src/interfaces/). These are C++ classes which follow
-[conventions](developer-notes.md#internal-interface-guidelines), like passing
+[conventions](../developer-notes.md#internal-interface-guidelines), like passing
 serializable arguments so they can be called from different processes, and
 making methods pure virtual so they can have proxy implementations that forward
 calls between processes.