docs: Add more explanation for ivhTreeviewBfs
docs: Add more explanation for ivhTreeviewBfs

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iVantage/angular-ivh-treeview,JeremyMarshall/angular-ivh-treeview,nbergqui/angular-ivh-treeview,NorthPage/angular-ivh-treeview,michal-husak/angular-ivh-treeview