Tendermint version: 0.22.8

Sorry for not following the bug template. This is a documentation bug, so most of that is irrelevant here.

DeliverTx can return, for a single transaction, several tags with the same key, since Tags is a list, not a map. The documentation is silent on whether it's allowed, and what will happen.

My current understanding from reading the code is that it works, and causes the transaction to be searchable using TxSearch("key='value'", ...) with either value. However, I'm not sure about ranges for numeric tags, and about whether subscriptions are going to work correctly.

I would like to use this if it's possible, but only if it's a documented feature rather than an unindended side effect.

On the other hand, if it is an unintended side effect, then duplicate tags should better be prohibited. The best way to do that is to define the tag set as a map rather than a slice.