Fix printing of type in lists and records

src/qir/ast/data/QIRLcons.java

@@ -36,7 +36,7 @@ public final class QIRLcons extends QIRList {
 
     @Override
     public final String toString() {
-        return "[ " + value + ", " + tail + "]" + (type == null ? "" : " : " + type);
+        return "[ " + value + ", " + tail + "]" + (type.isPresent() ? " : " + type : "");
     }
 
     @Override

src/qir/ast/data/QIRRcons.java

@@ -45,7 +45,7 @@ public final class QIRRcons extends QIRRecord {
 
     @Override
     public final String toString() {
-        return "{ " + id + ":" + value + "; " + tail + "}" + (type == null ? "" : " : " + type);
+        return "{ " + id + ":" + value + "; " + tail + "}" + (type.isPresent() ? " : " + type : "");
     }
 
     @Override