## What does this change do?
This pull request completes the change to the `metricsgen` metrics. It adds `go generate` directives to all of the files containing the `Metrics` structs.
Using the outputs of `metricsdiff` between these generated metrics and `master`, we can see that there is not a diff between the two sets of metrics when run locally.
```
[william@sidewinder] tendermint[wb/metrics-gen-transition]:. ◆ ./scripts/metricsgen/metricsdiff/metricsdiff metrics_master metrics_generated
[william@sidewinder] tendermint[wb/metrics-gen-transition]:. ◆
```
This change also adds parsing for a `metrics:` key in a field comment. If a comment line begins with `//metrics:` the rest of the line is interpreted to be the metric help text. Additionally, a bug where lists of labels were not properly quoted in the `metricsgen` rendered output was fixed.
This pull request adds an additional set of metrics targeted at providing more visibility into `abci++`.
The following set of metrics are added and exposed through the `metrics` endpoint:
```
tendermint_consensus_proposal_receive_count{chain_id="test-chain-IrF74Y",status="accepted"} 34
tendermint_consensus_proposal_create_count{chain_id="test-chain-IrF74Y"} 34
tendermint_consensus_vote_extension_receive_count{chain_id="test-chain-IrF74Y",status="accepted"} 34
tendermint_consensus_round_voting_power_percent{chain_id="test-chain-IrF74Y",vote_type="precommit"} 1
tendermint_consensus_round_voting_power_percent{chain_id="test-chain-IrF74Y",vote_type="prevote"} 1
tendermint_state_consensus_param_updates{chain_id="test-chain-IrF74Y"} 0
tendermint_state_validator_set_updates{chain_id="test-chain-IrF74Y"} 0
tendermint_consensus_late_votes{chain_id="test-chain-IrF74Y",vote_type="precommit"} 16
```
This pull request also updates the `metrics.md` file to include some metrics that were previously missed. My hope is to generate the `metrics.md` file with a future version of the tool being architected in #8479
