[Bug] PDF generation fails when TOC has many bookmarks about docfx

[filzrev]

I can also reproduce problems on my environment.

I've confirmed related source code. and it seems occurred when following condition met.

• IPage object is get from cached pools.
• Call GotoAsync with same page (but pointing different anchor(#))

docfx/src/Docfx.App/PdfBuilder.cs

Lines 144 to 156 in 6e116aa

	async Task<byte[]?> PrintPdf(Outline outline, Uri url)
	{
	await pageLimiter.WaitAsync();
	var page = pagePool.TryTake(out var pooled) ? pooled : await context.NewPageAsync();
	try
	{
	var response = await page.GotoAsync(url.ToString(), new() { WaitUntil = WaitUntilState.DOMContentLoaded });
	if (response?.Status is 404)
	return null;
	if (response is null || !response.Ok)
	throw new InvalidOperationException($"Failed to build PDF page [{response?.Status}]: {url}");

There is a document when response returns null.
https://playwright.dev/docs/api/class-page#page-goto

The method either throws an error or returns a main resource response. The only exceptions are navigation to about:blank or navigation to the same URL with a different hash, which would succeed and return null.