Function document_tabs 

pub fn document_tabs<K: Route, P: Piece, N, C>(
    tabs: TabSet<K>,
    new_label: impl IntoText<N>,
    close_label: impl IntoText<C>,
    title: impl Fn(&K) -> String + 'static,
    content: impl Fn(&K) -> P + 'static,
) -> DocumentTabs<K>

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