Add type definition to Vector Ecto type

[marcellofuschi]

Needed for tools like Dialyzer

[ericgross]

Thank you!

[ankane]

Hi @marcellofuschi, thanks for the PR. Can you share more about the issue you're seeing and how to reproduce it? Also, if it makes sense to add this for Vector, it probably makes sense to add for the other types.

[marcellofuschi]

I'm in a Phoenix project with Dialyzer. I have a typed_schema that has a Pgvector.Ecto.Vector field.
If I run Dialyzer in this setting, I get the following error:
Unknown type: Pgvector.Ecto.Vector.t/0.

The error disappears if I apply the change included in this PR.

[ankane]

Thanks @marcellofuschi. Added more typespecs in the commit above.

Also, for future reference, typed_ecto_schema is needed for typed_schema.