📖 (docs): Limit code rendering to relevant sections in multiversion webhook tutorial

Fixes #5232

Problem

The multiversion webhook tutorial was showing entire file contents instead of only the relevant code sections:

• Webhook v2: The entire webhook file was rendered, including imports, defaulting logic, and webhook setup
• main.go: Too much boilerplate was visible instead of focusing on the relevant setup sections

Root Cause

The generation scripts in hack/docs/internal/multiversion-tutorial/ were missing collapse markers to hide non-essential code from the rendered documentation.

Changes Made

File 1: hack/docs/internal/multiversion-tutorial/generate_multiversion.go

updateWebhookV2() function - Added imports collapse marker:

	// Add collapse marker after the import block to hide imports
	err = pluginutil.InsertCode(
		filepath.Join(sp.ctx.Dir, path),
		`batchv2 "tutorial.kubebuilder.io/project/api/v2"
)`,
		`

// +kubebuilder:docs-gen:collapse=Imports`)
	hackutils.CheckError("adding imports collapse marker to webhook v2", err)

updateMain() function - Added Manager Setup collapse marker (Lin:

	err = pluginutil.InsertCode(
		filepath.Join(sp.ctx.Dir, path),
		`if !enableHTTP2 {
		tlsOpts = append(tlsOpts, disableHTTP2)
	}`,
		`

	// +kubebuilder:docs-gen:collapse=Manager Setup`,
	)
	hackutils.CheckError("adding manager setup collapse marker main.go", err)

updateMain() function - Removed existing setup doc marker insertion :

	err = pluginutil.InsertCode(
		filepath.Join(sp.ctx.Dir, path),
		`if err := (&controller.CronJobReconciler{
		Client: mgr.GetClient(),
		Scheme: mgr.GetScheme(),
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "CronJob")
		os.Exit(1)
	}`,
		`
 `,
	)
	hackutils.CheckError("insert doc marker existing setup main.go", err)

File 2: hack/docs/internal/multiversion-tutorial/webhook_v2_implementaton.go

cronJobValidationFunction constant - Added collapse marker before validation functions :

 const cronJobValidationFunction = `
+// +kubebuilder:docs-gen:collapse=Webhook Setup and Defaulting

 // validateCronJob validates the fields of a CronJob object.
 func validateCronJob(cronjob *batchv2.CronJob) error {

Result

Webhook v2 (cronjob_webhook.go)

• Collapsed: Apache License, Imports, Webhook Setup and Defaulting
• Visible: Only validation functions (validateCronJob, validateCronJobName, validateCronJobSpec, validateScheduleFormat)

main.go

• Collapsed: Apache License, Imports, existing setup, Manager Setup (flags and HTTP2 config)
• Visible: Webhook TLS options, metrics server options, manager creation, controller setup, and webhook registration