Fix source mapping for code snippets

Signed-off-by: Ben Sherman <bentshermann@gmail.com>

Author: bentsherman

modules/compiler/src/main/java/script/parser/ScriptAstBuilder.java

@@ -228,6 +228,7 @@ private ModuleNode compilationUnit(CompilationUnitContext ctx) {
 
         if( !statements.isEmpty() ) {
             var main = block(new VariableScope(), statements);
+            ast( main, statements.get(0), statements.get(statements.size() - 1) );
             var workflowNode = workflowDef(main);
             moduleNode.addWorkflow(workflowNode);
             if( !hasDeclarations )