#1206 Updated the classDiagram JISON to not allow EOF or another '{' until first one is closed

src/diagrams/class/parser/classDiagram.jison

@@ -14,6 +14,8 @@
 \s+                     /* skip whitespace */
 "classDiagram"          return 'CLASS_DIAGRAM';
 [\{]                    { this.begin("struct"); /*console.log('Starting struct');*/return 'STRUCT_START';}
+<struct><<EOF>>         return "EOF_IN_STRUCT";
+<struct>[\{]            return "OPEN_IN_STRUCT";
 <struct>\}           { /*console.log('Ending struct');*/this.popState(); return 'STRUCT_STOP';}}
 <struct>[\n]              /* nothing */
 <struct>[^\{\}\n]*     { /*console.log('lex-member: ' + yytext);*/  return "MEMBER";}