“Thank you, have a good day!”, are the opening lines of limping Chang-bok (Yoo Jae-myung) as he sells eggs in a marketplace with his mute sidekick Tae-in (Yoo Ah-in, Burning, 2018) – and indeed, the friendliness of his words is complemented by the all-round sunniness of writer/director Hong Eui-jeong feature debut Voice of Silence (Sorido…