Fix em-dash/comma mismatch

chapters/packages.tex

@@ -85,9 +85,7 @@ \subsection{Importing Definitions from a Package}\doublelabel{importing-definiti
 
 \subsubsection{Lookup of Imported Names}\doublelabel{lookup-of-imported-names}
 
-This section only defines how the imported name is looked up in the
-import clause. For lookup in general -- including how import clauses are
-used, see \autoref{static-name-lookup}.
+This section only defines how the imported name is looked up in the import clause. For lookup in general --- including how import clauses are used --- see \autoref{static-name-lookup}.
 
 Lookup of the name of an imported package or class deviates from the normal lexical lookup.  For example, consider \lstinline!A.B.C! in the clauses \lstinline!import A.B.C;!, \lstinline!import D = A.B.C;!, or \lstinline!import A.B.C.*;!.
 Here, lookup starts with the lexical lookup of the first part of the name (\lstinline!A!) at the top-level.