chore: add non-empty .golangci.yml; fix whitespace lint issues

[alexandear]

This PR enables default linters for golangci-lint with whitespace linter, and fixes up whitespace lint issues.

In future, enable list may grow with new linters.

[mtrmac]

Thanks, but no.

The whitespace cleanups, sure, let’s merge them. But past experience with maintaining an 80-entry list of linters is that we … don’t. So let’s not take on the commitment.

[mtrmac]

Honestly I don’t want to be in the business of making these kinds of decisions. The defaults have worked pretty well so far, and related projects with these kinds of long lists have often ended up with long-unmaintained lists with no clear reasons. Compare containers/storage#1579 .

This also disables one of the currently default linters… while simultaneously carrying configuration for it. Let’s not.

[alexandear]

I changed the config to disable all linters and enable default linters and whitespace. Is it ok?

[mtrmac]

7 is better than ~80, but it’s still a list that is going to get out of date.

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WRT whitespace … I aesthetically like removing the empty lines, but the case is not that compelling. The result of adding that linter is that first-time external contributors use their preferred tooling, relying on standard gofmt or something like that… and the PR is later rejected, adding another roundtrip and extra friction for that contribution, for a trivial aesthetic reason.

[mtrmac]

I also worry that moving the build tags to the config is going to get out of sync.

[alexandear]

Won't do.