Extend linter rules (#1300)

- dupword checks for duplicate words in the source code
- durationcheck checks for two durations multiplied together
- forbidigo forbids identifiers
- mirror reports wrong mirror patterns of bytes/strings usage
- misspell finds commonly misspelled English words in comments
- predeclared finds code that shadows one of Go's predeclared identifiers
- thelper detects Go test helpers without t.Helper() call and checks the consistency of test helpers

management/server/account.go

@@ -1574,7 +1574,7 @@ func (am *DefaultAccountManager) GetAllConnectedPeers() (map[string]struct{}, er
 
 func isDomainValid(domain string) bool {
 	re := regexp.MustCompile(`^([a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,}$`)
-	return re.Match([]byte(domain))
+	return re.MatchString(domain)
 }
 
 // GetDNSDomain returns the configured dnsDomain