func (w *SnowballWord) RemoveFirstSuffixIfIn(startPos int, suffixes ...string) (suffix string, suffixRunes []rune) {
	suffix, suffixRunes = w.FirstSuffixIfIn(startPos, len(w.RS), suffixes...)
	if suffix != "" {
		w.RemoveLastNRunes(len(suffixRunes))
	}
	return
}
func (w *SnowballWord) RemoveFirstSuffixIfIn(startPos int, suffixes ...string) (suffix string, suffixRunes []rune) {
	suffix, suffixRunes = w.FirstSuffixIfIn(startPos, len(w.RS), suffixes...)
	if suffix != "" {
		w.RemoveLastNRunes(len(suffixRunes))
	}
	return
}
// Find the first suffix in the word among those provided; then,
// check to see if it begins after startPos.  If it does,
// remove it.
//