docs: Add anchors to each setting's name in settings.html for direct linking

[rmloveland]

In the docs, we'd like to be able to link to specific settings, as discussed during the review on cockroachdb/docs#4635

It can be done by manually adding anchors to the settings file copy in the docs repo. However, that file is auto-generated in this repo and then copied over periodically, so making edits via the docs repo would lead to conflicts that would need to be manually tracked and resolved.

Therefore this feature request is to add anchor tags to each setting in docs/generated/settings/settings.html so they can be linked to directly in the documentation. A solution (verified to work in the PR linked above) would be to add an anchor with the same name as the setting, e.g.

<tr><td><a name="sql.stats.automatic_collection.min_stale_rows"></a><code>sql.stats.automatic_collection.min_stale_rows</code></td><td>integer</td><td><code>500</code></td><td>target minimum number of stale rows per table that will trigger a statistics refresh</td></tr>

[arberiii]

How is settings.html file generated?

I found this line (https://github.com/cockroachdb/cockroach/blob/master/pkg/cmd/docgen/funcs.go#L218) which may be used to generate it but was not sure.

[rmloveland]

That looks like the place!

I think adding an anchor link somewhere in the tr might do it, e.g., something like the following (untested) code:

s := fmt.Sprintf("<tr><td><a name="%s"></a><code>%s(%s) &rarr; %s</code></td><td>%s</td></tr>", name, name, linkArguments(args), linkArguments(ret), extra)