Remove fully inactivated linters (#2148)

* Remove fully inactivated linters

Currently golangci-lint fails with these errors:

ERRO [linters_context] golint: This linter is fully inactivated: it will not produce any reports.
ERRO [linters_context] interfacer: This linter is fully inactivated: it will not produce any reports.
ERRO [linters_context] maligned: This linter is fully inactivated: it will not produce any reports.

I could not find any docs explaining what "fully inactivated" mean, but
based this PR[1] it seems that these linters do nothing now. Removing
the linters fixes this issue without changing linting, as they did not
produce any report.

Looking in the linters docs[2] I did not find a replacement for
"interfacer" and "malinged" linters. "stylecheck" seems to be a
replacement for "golint", but we need to fix the code to enable it.

[1] https://github.com/golangci/golangci-lint/pull/4436
[2] https://golangci-lint.run/usage/linters/

* Add stylecheck linter, replacement for golint

This revealed 2 capitalized error messages.

https://golangci-lint.run/usage/linters/#stylecheck