[defns.dynamic.type] Say "most derived object" in the example (#6203)

Author: frederick-vs-ja

source/intro.tex

@@ -243,8 +243,9 @@
 glvalue refers
 
 \begin{example}
-If a pointer\iref{dcl.ptr} \tcode{p} whose static type is ``pointer to
-class \tcode{B}'' is pointing to an object of class \tcode{D}, derived
+If a pointer\iref{dcl.ptr} \tcode{p} whose type is ``pointer to
+class \tcode{B}'' is pointing to a base class subobject
+of class \tcode{B}, whose most derived object is of class \tcode{D}, derived
 from \tcode{B}\iref{class.derived}, the dynamic type of the
 expression \tcode{*p} is ``\tcode{D}''. References\iref{dcl.ref} are
 treated similarly.