code: func (l *State) Remove(index int) {
  	apiCheckStackIndex(index, l.indexToValue(index))
  	i := l.callInfo.function + l.AbsIndex(index)
  	copy(l.stack[i:l.top-1], l.stack[i+1:l.top])
  	l.top--
  }
docs: // Remove the element at the given valid index, shifting down the elements
  // above index to fill the gap. This function cannot be called with a
  // pseudo-index, because a pseudo-index is not an actual stack position.
  //
  // http://www.lua.org/manual/5.2/manual.html#lua_remove