add gocritic/ruleguard checks back again, cleanup code. (#13665)

- remove some duplicated code
- reported a bug, separately fixed in #13664
- using strings.ReplaceAll() when needed
- using filepath.ToSlash() use when needed
- remove all non-Go style comments from the codebase

Co-authored-by: Aditya Manthramurthy <donatello@users.noreply.github.com>

cmd/bucket-replication-utils.go

@@ -172,7 +172,7 @@ func (o *ObjectInfo) TargetReplicationStatus(arn string) (status replication.Sta
 type replicateTargetDecision struct {
 	Replicate   bool   // Replicate to this target
 	Synchronous bool   // Synchronous replication configured.
-	Arn         string //ARN of replication target
+	Arn         string // ARN of replication target
 	ID          string
 }