fix: return proper AST from renamer

src/main/wacc/frontend/renamer.scala

@@ -233,7 +233,7 @@ object renamer {
         val bodyErrors = subscope.withSubscope { s => body.foldMap(rename(s)) }
         paramErrors ++ bodyErrors
       }
-    } yield (partialProg.self, errors)
+    } yield (Program(chunks.toList, main.body)(main.pos), errors)
   }
 
   // /** Check scoping of all variables and functions in the program. Also generate semantic types for