Update test cases to work on 3.11

[hillary-mutisya]

• use the pre-3.11 approach for declaring generic classes and typealiastype
• check for both typing.TypedDict and typing_extensions.TypedDict in _KNOWN_SPECIAL_BASES

[DanielRosenwasser]

Currently TypeChat only understands generics using 3.12 syntax. It doesn't consider types that extend Generic[...] or generic protocols as adding type parameters. So I think we either find a way to make some of these tests only run in 3.12, or temporarily disable them.

[hillary-mutisya]

I updated the TypeChat code to read type parameters for the classes that extend Generic[...] from the parameters field. With this, the generic_alias_1.py test now outputs type info correctly:

// Entry point is: 'FirstOrSecond'
// TypeScript Schema:

type FirstOrSecond<T> = First<T> | Second<T>

interface Second<T> {
    kind: "second";
    "second_attr": T;
}

interface First<T> {
    kind: "first";
    "first_attr": T;
}

[pcdeadeasy]

Looks good.

[hillary-mutisya]

Updated based on PR feedback