x/pkgsite: Syntax Highlight example blocks

[Rhymond]

What is the URL of the page with the issue?

Any page containing example block, e.g. https://pkg.go.dev/io#example-Copy

What is your user agent?

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.93 Safari/537.36

Screenshot

What did you do?

Open package documentation example

What did you expect to see?

Syntax Highlighted code block.

What did you see instead?

A text blob without syntax highlight

[Rhymond]

#40952 describes similar issue, but with comment code blocks. As I understand correctly it is hard to recognise comment code blocks language, however Example blocks are always (?) written in Go and can be highlighted.

[laoshaw]

many beginners like syntax highlight and golang is designed to be beginner friendly, why is this not even planned? golang is probably the only main language that insists all its doc, website using the plain code snippets, at least make syntax-highlight an opt-in please?

[hyangah]

Duplicate of #56081