[class.mem.general] Add missing \grammarterm and $...$

Author: tkoeppe

source/classes.tex

@@ -1018,7 +1018,7 @@
 describing the potential declaration of a non-static data member where
 \begin{itemize}
 \item $T$ is a type,
-\item $N$ is an identifier or $\bot$,
+\item $N$ is an \grammarterm{identifier} or $\bot$,
 \item $A$ is an alignment or $\bot$,
 \item $W$ is a bit-field width or $\bot$, and
 \item $\mathit{NUA}$ is a boolean value.
@@ -1041,7 +1041,7 @@
 is otherwise declared without an \grammarterm{alignment-specifier},
 \item
 it is a bit-field\iref{class.bit} with the width given by $W$
-if W is not $\bot$ and is otherwise not a bit-field, and
+if $W$ is not $\bot$ and is otherwise not a bit-field, and
 \item
 it is declared with
 the attribute \tcode{[[no_unique_address]]}\iref{dcl.attr.nouniqueaddr}