fix: osdate is not allowed in os.time

[Rathoz]

Using os.time() with an osdate type input is currently not allowed, only osdateparam is allowed.

---@type osdate
local date
dosomething(os.time(date))
--- Cannot assign `osdate` to parameter `osdateparam?`.
--- - `osdate` cannot match `osdateparam?`
--- - Type `osdate` cannot match `nil`
--- - Type `osdate` cannot match `osdateparam`Lua Diagnostics.(param-type-mismatch)

This simple change makes so that osdate is a child of osdateparam, and as such can be used in all curcumstances an osdateparam would be acceptable.