[class.ctor.general] Remove a dangling paragraph and associated index

The paragraph was made dangling by P1787R6.

Author: frederick-vs-ja

source/classes.tex

@@ -1301,10 +1301,6 @@
 \begin{note}
 For initialization of objects of class type see~\ref{class.init}.
 \end{note}
-
-\pnum
-\indextext{object!unnamed}%
-An object created in this way is unnamed.
 \begin{note}
 \ref{class.temporary} describes the lifetime of temporary objects.
 \end{note}