Populate missing ops in String method (#175)

To avoid displaying Unknown to known operations

Co-authored-by: Enrique J. Hernández <sixstone-qq@users.noreply.github.com>

v10/vm/op.go

@@ -70,9 +70,11 @@ const (
  // Set the field with the target index to nil
  NullField
 
+ // Hint at the final size of a map or an array for performance
  HintSize
 )
 
+// String implements Stringer interface.
 func (o Op) String() string {
  switch o {
  case Read:
@@ -117,6 +119,10 @@ func (o Op) String() string {
  return "set_long"
  case SetInt:
  return "set_int"
+ case NullField:
+ return "null_field"
+ case HintSize:
+ return "hint_size"
  }
  return "Unknown"
 }