hook.Add should not warn upon returning value in hook with no documented return value

[luttje]

This definition:

glua-api-snippets/library/hook.lua

Line 182 in 443fce9

---@overload fun(eventName: "PlayerLoadout", identifier: any, func: fun(ply: Player))

Results in this warning:

Despite the wiki not describing a return value for PlayerLoadout and similar hooks, since hook.Run will cease calling further hooks if any not-nil value is returned the code is valid and should not warn.

Perhaps if the hook has no return value on the wiki we should have it be any by default.

And untested, but there is likely a warning when the inverse happens, so in that case I guess we should have all returns in hooks be nillable.