resolveSibling
Adds relative file to this parent directory. If relative has a root or this has no parent directory, relative is returned back. For instance, File("/foo/bar").resolveSibling(File("gav")) is File("/foo/gav").
fun File.resolveSibling(relative: File): File(source)
import java.io.File
fun main() {
val original = File("/foo/bar")
val sibling = File("gav")
val resolved = original.resolveSibling(sibling)
println(resolved) // prints: /foo/gav
}