[conforming] bulletized opening paragraph and added reference to [res.on.contract.assertions]

Author: notadragon

source/lib-intro.tex

@@ -3554,12 +3554,17 @@
 Subclause \ref{conforming} describes the constraints upon, and latitude of, implementations of the \Cpp{} standard library.
 
 \pnum
-An implementation's use of headers is discussed in~\ref{res.on.headers}, its use
-of macros in~\ref{res.on.macro.definitions}, non-member functions
-in~\ref{global.functions}, member functions in~\ref{member.functions}, data race
-avoidance in~\ref{res.on.data.races}, access specifiers
-in~\ref{protection.within.classes}, class derivation in~\ref{derivation}, and
-exceptions in~\ref{res.on.exception.handling}.
+An implementation's use of
+\begin{itemize}
+\item headers is discussed in~\ref{res.on.headers},
+\item macros in~\ref{res.on.macro.definitions},
+\item non-member functions in~\ref{global.functions},
+\item member functions in~\ref{member.functions},
+\item data race avoidance in~\ref{res.on.data.races},
+\item access specifiers in~\ref{protection.within.classes},
+\item class derivation in~\ref{derivation},
+\item exceptions in~\ref{res.on.exception.handling}, and
+\item contract assertions in~\ref{res.contract.assertions}.
 
 \rSec3[res.on.headers]{Headers}