[macros] Change \nontermdef so that the colon is styled as normal, not-italicized text

The colon is not part of the name of the grammar production which it follows, so it should not be styled like a grammar production name.

Author: tkoeppe

source/macros.tex

@@ -393,9 +393,9 @@
 
 \newenvironment{bnfbase}
  {
- \newcommand{\nontermdef}[1]{\nonterminal{##1}\indexgrammar{\idxgram{##1}}:}
+ \newcommand{\nontermdef}[1]{\nonterminal{##1\itcorr}\indexgrammar{\idxgram{##1}}\textnormal{:}}
  \newcommand{\terminal}[1]{{\BnfTermshape ##1}\xspace}
- \newcommand{\descr}[1]{\normalfont{##1}}
+ \newcommand{\descr}[1]{\textnormal{##1}}
  \newcommand{\bnfindentfirst}{\BnfIndent}
  \newcommand{\bnfindentinc}{\BnfInc}
  \newcommand{\bnfindentrest}{\BnfRest}