[class.prop] Clarify definition of implicit-lifetime class (#5319)

Author: jensmaurer

source/classes.tex

@@ -302,10 +302,14 @@
 \end{note}
 
 \pnum
-A class \tcode{S} is an \defnadj{implicit-lifetime}{class}
-if it is an aggregate or
-has at least one trivial eligible constructor and
+A class \tcode{S} is an \defnadj{implicit-lifetime}{class} if
+\begin{itemize}
+\item
+it is an aggregate or
+\item
+it has at least one trivial eligible constructor and
 a trivial, non-deleted destructor.
+\end{itemize}
 
 \rSec1[class.name]{Class names}
 \indextext{definition!class name as type}%