Get the indexes of all letters in a given word as a list of integers

getIndexesOfLetters.kt

/**
* Searches for all indexes of a given character in a word. The search is not case sensitive.
* @param c the char to search for
* @param word the word to look in
* @return list with indexes where the char matches
*/
fun getIndexesOfLetters(c: Char, word: String): List<Int> {
    return word
        .lowercase()
        .withIndex()
        .filter { it.value == c }
        .map { it.index }
}