tell latex how to hyphenate "expression-equivalent"

Author: ericniebler

source/exec.tex

@@ -1901,9 +1901,9 @@
 \tcode{decltype(e)} models \exposconcept{queryable} and
 \item
 given a query object \tcode{q},
-the expression \tcode{e.query(q)} is expression-equivalent
+the expression \tcode{e.query(q)} is ex\-pres\-sion-equiv\-alent
 to \tcode{state.query(q)} if that expression is valid,
-otherwise, \tcode{e.query(q)} is expression-equivalent
+otherwise, \tcode{e.query(q)} is ex\-pres\-sion-equiv\-alent
 to \tcode{get_env(rcvr).query(q)}.
 \end{itemize}
 \end{itemdescr}