[meta.reflection.layout] Fix wording of alignment_of.

The original transcription used some older wording that was not in the
most recent (approved) revision of paper (P2996R13).

Author: tkoeppe

source/meta.tex

@@ -5751,19 +5751,18 @@
 \begin{itemize}
 \item
   If \tcode{dealias(r)} represents a type $T$,
-  then the alignment requirement for the layout-associated type\iref{class.mem.general}
-  for a non-static data member of type $T$.
+  then \tcode{alignment_of(add_pointer(r))} if $T$ is a reference type
+  and the alignment requirement of $T$ otherwise.
 \item
   Otherwise, if \tcode{dealias(r)} represents a variable or object,
   then the alignment requirement of the variable or object.
 \item
   Otherwise, if \tcode{r} represents a direct base class relationship,
   then \tcode{alignment_of(type_of(r))}.
 \item
-  Otherwise, if \tcode{r} represents a non-static data member,
-  then the alignment requirement of the subobject
-  associated with the represented entity
-  within any object of type \tcode{parent_of(r)}.
+  Otherwise, if \tcode{r} represents a non-static data member $M$ of a class $C$,
+  then the alignment of the direct member subobject
+  corresponding to $M$ of a complete object of type $C$.
 \item
   Otherwise, \tcode{r} represents a data member description
   $(T, N, A, W, \mathit{NUA})$\iref{class.mem.general}.