test(cmd): improve error handling in completion test writer close

Handle potential errors when closing the pipe writer in TestCompletionCmd,
and use a deferred anonymous function to ignore errors in defer.

cmd/completion_test.go

@@ -26,10 +26,12 @@ func TestCompletionCmd(t *testing.T) {
 				t.Fatal(err)
 			}
 			os.Stdout = w
-			defer w.Close()
+			defer func() { _ = w.Close() }()
 			cmd := &cobra.Command{}
 			completionCmd.Run(cmd, []string{tt.shell})
-			w.Close()
+			if err := w.Close(); err != nil {
+				t.Errorf("close: %v", err)
+			}
 			b, err := io.ReadAll(r)
 			if err != nil {
 				t.Fatal(err)