Exposing the Oid of PostgreSQL types

[Razican]

This PR closes #1111 and supersedes #2146. It adds a function to retrieve OIDs, which is very useful in very dynamic schemas, such as DBMSs or when you want to provide a more low-level interface to the DB.

This function is a non-panicking alternative to .oid().

[Razican]

@abonander is this a better solution to the situation? Could this be reviewed?

[abonander]

This is fine as long as the documentation is very clear about the caveats. The suggested change has those.

The try_ prefix of the method suggests that the implementation will attempt to look up the OID, so that should be omitted.

[Razican]

This is fine as long as the documentation is very clear about the caveats. The suggested change has those.

The try_ prefix of the method suggests that the implementation will attempt to look up the OID, so that should be omitted.

Makes total sense to me :) I added your changes to the PR. Thanks for reviewing it!

[abonander]

@Razican can you run cargo fmt real quick? It doesn't like something in my suggested change but it's not obvious what (maybe a Tab character got in there somehow).

[Razican]

@Razican can you run cargo fmt real quick? It doesn't like something in my suggested change but it's not obvious what (maybe a Tab character got in there somehow).

Done :)