He thinks putting an apostrophe there signals that it's an informal slangy spelling. Probably thinking of "Li'l Abner" and the like. He's putting it at the end because he's not sure what to do with it, with no letters skipped...
He may even have convinced himself that "Liddle'" is the correct spelling of "Li'l".
And he said hyphen but meant apostrophe.
It reminds me of the first time he took over the press briefing from Spicer and went out and rambled incoherently then said "and that's how it's done."
Him being his own best advocate is the most cherished myth of his self-image...
This is his genuine character. Is it distracting? Sure. Does he know how to use distractions to how advantage? He has to, because he keeps making them.
No one said anything because no one wanted to be the one who had told him he had toilet paper on his shoe.
No one is going to brush the metaphorical crumbs off his shirt for him right now.