[class.dtor, cpp.cond] Add missing \grammarterm. (#1469)

Author: Eelis

source/preprocessor.tex

@@ -309,7 +309,7 @@
 \tcode{true}
 and
 \tcode{false},
-are replaced with the pp-number
+are replaced with the \grammarterm{pp-number}
 \tcode{0},
 and then each preprocessing token is converted into a token.
 \begin{note}

source/special.tex

@@ -1197,7 +1197,7 @@
 \end{example}
 \begin{note}
 An explicit destructor call must always be written using
-a member access operator~(\ref{expr.ref}) or a qualified-id~(\ref{expr.prim});
+a member access operator~(\ref{expr.ref}) or a \grammarterm{qualified-id}~(\ref{expr.prim});
 in particular, the
 \grammarterm{unary-expression}
 \tcode{\~{}X()}