Heading Icon

How can I add an icon to

getHeading

getHeading

getHeading

getHeading method from ViewRecord?

public function getHeading(): string
    {
        return "Viewing  text <icon here>";
    }

public function getHeading(): string
    {
        return "Viewing  text <icon here>";
    }

public function getHeading(): string
    {
        return "Viewing  text <icon here>";
    }

public function getHeading(): string
    {
        return "Viewing  text <icon here>";
    }