Merge pull request kubernetes#127869 from ak20102763/explain_o_shorthand

Added shorthand for kubectl explain --output

Author: k8s-ci-robot

staging/src/k8s.io/kubectl/pkg/cmd/explain/explain.go

@@ -96,7 +96,7 @@ func NewCmdExplain(parent string, f cmdutil.Factory, streams genericiooptions.IO
 	o := NewExplainOptions(parent, streams)
 
 	cmd := &cobra.Command{
-		Use:                   "explain TYPE [--recursive=FALSE|TRUE] [--api-version=api-version-group] [--output=plaintext|plaintext-openapiv2]",
+		Use:                   "explain TYPE [--recursive=FALSE|TRUE] [--api-version=api-version-group] [-o|--output=plaintext|plaintext-openapiv2]",
 		DisableFlagsInUseLine: true,
 		Short:                 i18n.T("Get documentation for a resource"),
 		Long:                  explainLong + "\n\n" + cmdutil.SuggestAPIResources(parent),
@@ -111,7 +111,7 @@ func NewCmdExplain(parent string, f cmdutil.Factory, streams genericiooptions.IO
 	cmd.Flags().StringVar(&o.APIVersion, "api-version", o.APIVersion, "Use given api-version (group/version) of the resource.")
 
 	// Only enable --output as a valid flag if the feature is enabled
-	cmd.Flags().StringVar(&o.OutputFormat, "output", plaintextTemplateName, "Format in which to render the schema. Valid values are: (plaintext, plaintext-openapiv2).")
+	cmd.Flags().StringVarP(&o.OutputFormat, "output", "o", plaintextTemplateName, "Format in which to render the schema. Valid values are: (plaintext, plaintext-openapiv2).")
 
 	return cmd
 }