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
