Replace en-dash by parentheses when giving non-normative rationale

chapters/scoping.tex

@@ -545,9 +545,7 @@ \subsubsection{Steps of Instantiation}\doublelabel{steps-of-instantiation}
 (\autoref{annotations-for-simulation-experiments}) or functions (\autoref{declaring-derivatives-of-functions}, \autoref{declaring-inverses-of-functions} and \autoref{external-function-interface}).
 \end{nonnormative}
 
-Extends clauses are not looked up, but empty extends clause nodes are
-created and inserted into the current instance -- to be able to preserve
-the declaration order of components.
+Extends clauses are not looked up, but empty extends clause nodes are created and inserted into the current instance (to be able to preserve the declaration order of components).
 
 \paragraph*{The inherited contents of the element}\doublelabel{the-inherited-contents-of-the-element}