Function menu_heading 

pub fn menu_heading(theme: &Theme, label: impl Into<SharedString>) -> Div

Small uppercase section heading inside a floating menu (the reference MenuHeading): px-2 pb-1 pt-1.5 uppercase tracking-[0.1em] text-muted-foreground/60. gpui has no letter-spacing at the pinned rev; the tracking is approximated with hair spaces.