code: func (c *ChainIndexer) removeSectionHead(section uint64) {
  	var data [8]byte
  	binary.BigEndian.PutUint64(data[:], section)
  
  	c.indexDb.Delete(append([]byte("shead"), data[:]...))
  }
docs: // removeSectionHead removes the reference to a processed section from the index
  // database.