metrics: transition all metrics to using metricsgen generated constructors. (port of #8488) (#9178)

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 `main`, we can see that there is a minimal diff between the two sets of metrics when run locally. The diff here stems from removal of the word 'message' which was done in v0.36+ and is ultimately a better phrasing. This metric has not yet been released, so this phrasing is preferred.

```
./metricsdiff old new
Metric changes:
+++ tendermint_consensus_full_prevote_delay
+++ tendermint_consensus_quorum_prevote_delay
--- tendermint_consensus_full_prevote_message_delay
--- tendermint_consensus_quorum_prevote_message_delay
```

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.

In my view, docs and tests are not needed for this internal only change.

---
#### PR checklist

- [ ] Tests written/updated, or no tests needed
- [ ] `CHANGELOG_PENDING.md` updated, or no changelog entry needed
- [ ] Updated relevant documentation (`docs/`) and code comments, or no
      documentation updates needed

Ports #8488 to main

consensus/state.go

@@ -2323,12 +2323,12 @@ func (cs *State) calculatePrevoteMessageDelayMetrics() {
 		_, val := cs.Validators.GetByAddress(v.ValidatorAddress)
 		votingPowerSeen += val.VotingPower
 		if votingPowerSeen >= cs.Validators.TotalVotingPower()*2/3+1 {
-			cs.metrics.QuorumPrevoteMessageDelay.Set(v.Timestamp.Sub(cs.Proposal.Timestamp).Seconds())
+			cs.metrics.QuorumPrevoteDelay.Set(v.Timestamp.Sub(cs.Proposal.Timestamp).Seconds())
 			break
 		}
 	}
 	if ps.HasAll() {
-		cs.metrics.FullPrevoteMessageDelay.Set(pl[len(pl)-1].Timestamp.Sub(cs.Proposal.Timestamp).Seconds())
+		cs.metrics.FullPrevoteDelay.Set(pl[len(pl)-1].Timestamp.Sub(cs.Proposal.Timestamp).Seconds())
 	}
 }