Changed the error margin markers to use red text

Author: eernstg

specification/dart.sty

@@ -199,11 +199,11 @@
 
 % Mark a compile-time error in the margin.
 \newcommand{\Error}[1]{%
-  \leavevmode\marginpar{\ensuremath{\ominus}}{#1}}
+  \leavevmode\marginpar{\ensuremath{\textcolor{red}{\ominus}}}{#1}}
 
 % Mark a dynamic error in the margin.
 \newcommand{\DynamicError}[1]{%
-  \leavevmode\marginpar{\Lightning}{#1}}
+  \leavevmode\marginpar{\textcolor{red}{\Lightning}}{#1}}
 
 % Used to specify comma separated lists of similar symbols.
 \newcommand{\List}[3]{\ensuremath{{#1}_{#2},\,\ldots,\ {#1}_{#3}}}