Add reference to sensors for stream.

chapters/annotations.tex

@@ -506,7 +506,7 @@ \subsection{Connection Restrictions}\label{connection-restrictions}
 This annotation is intended for non-causal connectors, see \cref{restrictions-of-connections-and-connectors}.
 The connection handling operates on connection sets, and thus this restriction should also operate on those sets.
 The set handling avoids the case where only one of two equivalent models generate diagnostics.
-The stream connector part is primarily intended to exclude sensor-variables, but also excludes non-reversible outgoing flows.
+The stream connector part is primarily intended to exclude sensor-variables, see \cref{connection-of-3-stream-connectors-where-one-mass-flow-rate-is-identical-to-zero-n-3-and}, but also excludes non-reversible outgoing flows.
 \end{nonnormative}
 
 \begin{example}