Provide mechanism to get record type

It would be convenient to have some method on a `RecordWrapper` that allows retrieving the record's type. For example, a `get_type()` record might return a string `ao`, to say that this record is an Analog Out type, or `bi` for Boolean In, etc.

This would allow users to query `RecordWrapper` instances dynamically to know what keyword arguments `set()` allows, for example.

Start by locating the RecordWrapper implementation and the set() handling it exposes. Trace how record types and accepted keyword arguments are represented, then define what get_type() should return for examples such as ao and bi. Done means callers can retrieve the record type reliably and the behavior is covered by tests.

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