Returns the number of code points up to code_units characters

Property definitions

core $ UCharString :: code_points
	# Returns the number of code points up to `code_units` characters
	fun code_points(code_units: Int): Int `{
		if (self == NULL) {
			return -1;
		}
		return u_countChar32(self, code_units);
	`}
lib/core/text/u16_string.nit:157,2--163,3