DNM Test with reference docs using Goldmark in istio/api

[ericvn]

Please provide a description for what this PR is for.

Test deploy using updated tooling to generate with Goldmark instead of BlackFriday (istio/tools#2168).

Ran make gen against istio/api and then updated the docs from my repo's branch.

[ericvn]

Need to fix:

Error: Error building site: "/work/content/zh/docs/reference/config/networking/destination-rule/index.html:1:1": unrecognized character in shortcode action: U+0021 '!'. Note: Parameters with non-alphanumeric args must be quoted

found with make serve

[ericvn]

Related to changes like:?

 - <p>{{<tabset category-name="example">}}
 - {{<tab name="v1alpha3" category-value="v1alpha3">}}</p>

 + <p>{{<!-- raw HTML omitted -->}}<br />
 + {{<!-- raw HTML omitted -->}}</p>

[ericvn]

Updated the markdown to add Unsafe and remove XHTML and hard breaks. Reran against api and to istio.io.

[ericvn]

var md = goldmark.New(
	goldmark.WithExtensions(extension.GFM),
	goldmark.WithParserOptions(
		parser.WithAutoHeadingID(),
	),
	goldmark.WithRendererOptions(
		html.WithUnsafe(),
	),
)

in md.go yields this. The Deploy looks good. I noticed only one bit of weirdness in formatting, but the actually displayed text is the same. The issue is really that the formatting in istio/api is incorrect in this case and should be fixed.

[ericvn]

Close this PR as testing is hopefully complete.