align kubo with unified golang ci linter from IPDX and
rules used in boxo and other go packages
addressed lint rules:
- ST1000: added package comments
- ST1020, ST1021, ST1022: fixed function/method comments
- QF1001: applied De Morgan's law
- QF1003: converted if-else chains to tagged switches
- QF1004: replaced strings.Replace with strings.ReplaceAll
- QF1008: simplified embedded struct field selectors
- unconvert: removed unnecessary type conversions
- usestdlibvars: used stdlib constants instead of literals
disabled errcheck linter in .golangci.yml
4f4dac9564