add two missing items

Doc/lib/libdis.tex

@@ -78,6 +78,10 @@ for compatibility with earlier Python releases.
 Sequence of operation names, indexable using the byte code.
 \end{datadesc}
 
+\begin{datadesc}{opmap}
+Dictionary mapping byte codes to operation names.
+\end{datadesc}
+
 \begin{datadesc}{cmp_op}
 Sequence of all compare operation names.
 \end{datadesc}
@@ -688,3 +692,9 @@ Calls a function. \var{argc} is interpreted as in
 keyword arguments dictionary, followed by the variable-arguments
 tuple, followed by explicit keyword and positional arguments.
 \end{opcodedesc}
+
+\begin{opcodedesc}{HAVE_ARGUMENT}{}
+This is not really an opcode.  It identifies the dividing line between
+opcodes which don't take arguments \code{< HAVE_ARGUMENT} and those which do
+\code{>= HAVE_ARGUMENT}.
+\end{opcodedesc}