contains
Returns whether the path identified by pointer resolves to a value within this element.
Distinguishes "absent" from "present and net.mamoe.yamlkt.YamlNull": a path whose value is net.mamoe.yamlkt.YamlNull returns true.
Return
true if the path resolves to a value (including net.mamoe.yamlkt.YamlNull); false if any segment is absent or out of bounds, or if the path attempts to navigate into a primitive.
Parameters
pointer
The KPointer to test.