fix: variable-sized values, heap-allocated arrays (and printCharArray)

src/main/wacc/Main.scala

@@ -1,6 +1,7 @@
 package wacc
 
 import scala.collection.mutable
+import cats.data.Chain
 import parsley.{Failure, Success}
 import scopt.OParser
 import java.io.File
@@ -63,7 +64,7 @@ def frontend(
 }
 
 val s = "enter an integer to echo"
-def backend(typedProg: microWacc.Program): List[asm.AsmLine] =
+def backend(typedProg: microWacc.Program): Chain[asm.AsmLine] =
   asmGenerator.generateAsm(typedProg)
 
 def compile(filename: String, outFile: Option[File] = None)(using