Adapt IDBTransaction & IDBDatabase events to the new event structure

[teoli2003]

Part of #14578.

Per the new guideline: https://github.com/mdn/browser-compat-data/blob/main/docs/data-guidelines.md#dom-events-eventname_event

Events affected:
On IDBTransaction: abort_event and error_event are bubbling, complete_event not.
On IDBDatabase: close_event and versionchange_event events.

Content work: mdn/content#13040
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[saschanaz]

I'm not sure I understand this, why remove IDBDatabase.abort_event and IDBDatabase.error_event? Which fields correspond to those events now?

Opened #15345.

[queengooborg]

Coming from #15345, I did a little digging into this and found that the IDBDatabase has event handlers for abort and error -- see https://w3c.github.io/IndexedDB/#database-interface. I believe that we should keep abort_event and error_event subfeatures on the IDBDatabase interface as a result. @Elchi3 @teoli2003, what do you think?

[teoli2003]

I agree that what we do for bubbling events may not be optimal. I'm thinking of writing down the use cases. Something like:
"As a web developer, I want to be able to know if I have to set up the event handler on object X or on its container Y"
and so on.

There are likely other use cases, though.