Validate gocritic settings. Return error if settings includes a unsupported gocritic checker

[sebastien-rosset]

This PR performs additional gocritic settings validation. The settings attribute is supposed to be a map where each key is the name of a supported gocritic checker.

The existing validation already warns if the config data contains a settings for a disabled checker. But it does not validate the checker is supported. There is also an existing validation that the specific parameter is supported or not.

For example, as shown in the yaml config data below, ruleguard is a supported gocritic checker, but rangeValueCopy is not (the actual checker is rangeValCopy).

  gocritic:
    settings:
      rangeValueCopy:
        sizeThreshold: 32
      ruleguard:
        rules: myrules.go

[CLAassistant]

All committers have signed the CLA.

[sebastien-rosset]

Note: I've noticed a separate but related problem: if the input ruleguard rules.go has a syntax error, the error is silently ignored and the entire ruleguard file is ignored. This is unlike the gocritic and ruleguard behavior which print an error message and exit with error status. I'm trying to find why this is happening.

[sebastien-rosset]

@quasilyte, would you be able to review this PR? thank you.

[quasilyte]

Looks good.

[sebastien-rosset]

@ldez , I see you have removed two reviewers. I had added them because they seemed to be the most recent committers for this file. Are you the reviewer?

[ldez]

From my point of view, it's better to let people add themselves as reviewers if they want to review.