Fix Request: Kotlin AvoidRecreatingDateTimeFormatter false positive

[jborgers]

The rule doesn't recognize object as being a singleton and val for a constant.

object DateUtil {
    private const val ISO8601_PATTERN = "yyyyMMdd'T'HHmmss'Z'"
    private val DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern(ISO8601_PATTERN) // <-- false positive

    fun formatISO8601(dateTime: ZonedDateTime): String =
        dateTime.withZoneSameInstant(ZoneOffset.UTC)
            .format(DATE_TIME_FORMATTER)
}

[stokpop]

Also for these contructs, format can also be on String (and other types?):

class Foo() {
    fun originalDate(rule: Rule): String? =
        rule.date?.format(DateTimeFormatter.ISO_DATE) // <-- false positive
}

class Rule(val name: String, val regex: String, val date: LocalDate?)