kubectl explain: ignore trailing period

kubectl explain ingress.spec.rules.http.paths. is valid
and defaults to kubectl explain ingress.spec.rules.http.paths

Rational: We use kubectl explain by adding fields
(e.g. service, then service.spec, then service.spec.ports ...)
so it's very easy to forget a trailing . at the end. We should
ignore the trailing period and display the result without it.

pkg/kubectl/explain/explain.go

@@ -30,6 +30,10 @@ type fieldsPrinter interface {
 
 func splitDotNotation(model string) (string, []string) {
 	var fieldsPath []string
+
+	// ignore trailing period
+	model = strings.TrimSuffix(model, ".")
+
 	dotModel := strings.Split(model, ".")
 	if len(dotModel) >= 1 {
 		fieldsPath = dotModel[1:]