Generic classes do not include their base class by default

```lua
---@class A<T> : { typed_dummy: T }
---@field dummy number

---@type A<number>
local a

local b = a.typed_dummy -- ok
local c = a.dummy -- warning, undefined field
```
```lua
---@class A<T> : { typed_dummy: T }
---@field dummy number

---@type A<number>|A
local a

local b = a.typed_dummy -- ok
local c = a.dummy -- now ok too
```