A RichText panel class that replaces matches of the regex '\b[Bb]oomerang-items?\b' with an icon. It sets ImagePath to 'textures/ui/boomerang.png' and hides the matched text.
using Sandbox;
[RichTextPanel( @"\b[Bb]oomerang-items?\b" )]
public class RichTextBoomerangIcon : RichTextBase
{
public override string ImagePath => "textures/ui/boomerang.png";
public override bool HideText => true;
}