Type alias support

[snorkysnark]

For type aliases, one can either use the 3.12 syntax:

type Resolves[T] = T | OutputOf

which results in an error: WARNING: ralsei.graph.outputof: ralsei.graph.outputof: 'Resolves' is unknown [autodoc2.all_resolve]

or the older

Resolves: TypeAlias = T | OutputOf

which works but obscures the value: ralsei.graph.outputof.Resolves : TypeAlias = None

So there isn't a good way to document type aliases and what they refer to.
Sure you can replace them with autodoc2_replace_annotations, but I'd like the user to know what aliases exist as part of my API