[expr.const] Improve punctuation in list items.

Striking "and" was a missed edit from P2996R13.

Author: tkoeppe

source/expressions.tex

@@ -8997,7 +8997,7 @@
 a glvalue core constant expression $E$ for which
 \begin{itemize}
 \item
-$E$ refers to a non-immediate function
+$E$ refers to a non-immediate function,
 \item
 $E$ designates an object \tcode{o}, and
 if the complete object of \tcode{o} is of consteval-only type then so is $E$,
@@ -9026,15 +9026,15 @@
 no constituent value of scalar type is an indeterminate or erroneous value\iref{basic.indet},
 \item
 no constituent value of pointer type is a pointer to an immediate function or
-an invalid pointer value\iref{basic.compound}, and
+an invalid pointer value\iref{basic.compound},
 \item
 no constituent value of pointer-to-member type designates an immediate function, and
 \item
 unless the value is of consteval-only type,
 \begin{itemize}
 \item
 no constituent value of pointer-to-member type points to
-a direct member of a consteval-only class type
+a direct member of a consteval-only class type,
 \item
 no constituent value of pointer type points to or past an object
 whose complete object is of consteval-only type, and