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>

internal/rest/client_test.go

@@ -54,6 +54,7 @@ func TestNetworkError_Unwrap(t *testing.T) {
 			n := &NetworkError{
 				Err: tt.err,
 			}
+			//nolint:gocritic
 			if tt.target == nil {
 				var netErrInterface net.Error
 				if errors.As(n, &netErrInterface) != tt.want {