snowballword/snowballword.go
func (w *SnowballWord) FitsInRV(x int) bool {
	return w.RVstart <= len(w.RS)-x
}
func (w *SnowballWord) FitsInRV(x int) bool {
	return w.RVstart <= len(w.RS)-x
}
// Returns true if `x` runes would fit into RV.
//