improvement: Expose hwmon collector config options in prometheus.exporter.unix component.

[dtrejod]

PR Description

Exposes hwmon collector config options in the prometheus.exporter.unix component. The hwmon collector currently in the last v1.8.2 release of node_exporter supports hwmon configuration for which hwmon chips to filter to. This is useful for those users that just want a subset of hwmon metrics, and don't want to list a collection of relabel_rules to drop irrelevant hwmon metrics.

https://github.com/prometheus/node_exporter/blob/f1e0e8360aa60b6cb5e5cc1560bed348fc2c1895/collector/hwmon_linux.go#L35-L36

Which issue(s) this PR fixes

n/a

Notes to the Reviewer

A recent PR to node_exporter also added support for filtering on sensors. However these is not a release of node_exporter that has this change yet therefore I didn't include it in this PR
prometheus/node_exporter@e11a4f0

PR Checklist

• CHANGELOG.md updated
• Documentation added
• Tests updated
• Config converters updated

[clayton-cornell]

These descriptions are.... hard to understand.

1. We try to avoid using brackets in the text descriptions.
2. If you do use brackets like this, it's for additional information and the text should make sense without the bracketed additional info. If I take out the bracketed info I'm left with Regexp of hwmon chip to which is incomplete.

Sometimes people use brackets for info that would fit just fine within the sentence. Even taking out the just brackets and leaving the text, I'm unable to really understand the description.

[wildum]

The doc here is not correct, the correct version should be:

• Regexp of hwmon chip to include (mutually exclusive to chip-exclude).
• Regexp of hwmon chip to exclude (mutually exclusive to chip-include).

If we want to avoid the brackets, I would suggest the following:

• Regexp of hwmon chip to include
• Regexp of hwmon chip to exclude

And below we can add a text saying "chip_include and chip_exclude are mutually exclusive".

@clayton-cornell feel free to change the wording

[clayton-cornell]

Now it makes a LOT more sense. Thanks.

[dtrejod]

I poorly copied the upstream help docs. Updated to use the proposed new wording.

[clayton-cornell]

Looks good now.

[wildum]

LGTM, thanks for adding this!