Add several missing trio.Path methods that wrap pathlib.Path methods added in 3.5; I missed them originally because they were declared in a different part of the typeshed stubs for stdlib Path.
Make the iteration methods return trio.Path rather than pathlib.Path to match new-ish upstream trio behavior.
trio.Pathmethods that wrappathlib.Pathmethods added in 3.5; I missed them originally because they were declared in a different part of the typeshed stubs for stdlibPath.trio.Pathrather thanpathlib.Pathto match new-ish upstream trio behavior.