Fix extra spacing at start of bnf entries.

doc/macros.tex

@@ -28,7 +28,7 @@
 \newcommand{\sep}{ \\[2mm] \spacefalse\newentrytrue}
 \newcommand{\newl}{ \\ & & \spacefalse}
 \newcommand{\alt}{ \\ & $\mid$ & \spacefalse}
-\newcommand{\is}{ & $::=$ & \newentryfalse}
+\newcommand{\is}{ & $::=$ & \spacefalse\newentryfalse}
 \newenvironment{syntax}{\begin{tabular}{@{}rrll@{}}\spacefalse\newentrytrue}{\end{tabular}}
 \newcommand{\synt}[1]{$\spacefalse#1$}
 \newcommand{\emptystring}{$\epsilon$}