Merge #3089

3089: Fix some links to mini-protocol code in documentation r=coot a=kantp

A few of the links from the documentation to the code of mini protocols broke
during refactoring.

Co-authored-by: Philipp Kant <philipp.kant@iohk.io>
Co-authored-by: Marcin Szamotulski <profunctor@pm.me>

docs/network-spec/miniprotocols.tex

@@ -256,6 +256,7 @@ \subsection{Ping-Pong Protocol}
 \newcommand{\Ping}{\msg{MsgPing}}
 \newcommand{\Pong}{\msg{MsgPong}}
 
+
 \subsubsection{Description}
 A client can use the Ping-Pong protocol to check that the server is responsive.
 The Ping-Pong protocol is very simple because the messages do not carry any data and
@@ -316,6 +317,8 @@ \subsubsection{Description}
 application of the protocol determines the types of the requests and responses.
 
 \subsubsection{State machine}
+\haddockref{Network.TypedProtocol.ReqResp.Type}{typed-protocols-examples/Network-TypedProtocol-ReqResp-Type.html#t:ReqResp}
+
 
 \begin{tabular}{|l|l|}
   \hline