Setting MarkDownTextView.onDidConvertMarkDownItemToView does not work

[majsty]

Marky-Mark information

• Marky-Mark version: 10.1.4
• MarkDownConfiguration: view (View, AttributedString)

Describe the bug

I have set up a MarkDownTextView via xib, and am attempting to set onDidConvertMarkDownItemToView via the didSet of the outlet as so:

    @IBOutlet weak var markDownTextView: MarkDownTextView! {
        didSet {
            self.markDownTextView.onDidConvertMarkDownItemToView = { item, view in
               // doesn't get called
            }
        }
    }

Unfortunately onDidConvertMarkDownItemToView never gets called. Am I doing something wrong? I have made a PR to fix this: #118