x/pkgsite: deprecated UI is overly repetitive

[mvdan]

Take a look at https://pkg.go.dev/path/filepath#HasPrefix:

I see deprecated as many as three times: next to the declaration in the form of a label, in the "This function has been deprecated." notice below, and in the "Deprecated:" text in the original godoc.

I get that the label should be there, to still be clear when one presses "hide". And that the "Deprecated:" text is part of the original godoc, so we should probably not alter the text.

That leaves me with the extra notice in between, which I think doesn't add much information. Here's an example of how it looks like when we remove that extra notice - in my opinion, better:

cc @julieqiu

[julieqiu]

That makes sense to me.

/cc @jinhongy @fflewddur @jamalc for input

[mvdan]

It's also perhaps amusing that HasPrefix is named four times, but I don't think we can blame that on the deprecation UI. The rest of the UI already consistently repeats each name twice, and the godoc as-is has the name two more times.

[mibk]

I would also suggest putting the "Deprecated:" prefix in bold to highlight its importance.

[gopherbot]

Change https://golang.org/cl/355189 mentions this issue: static/doc: less repetative deprecation UI