x/tools/gopls: deprecate 'Structured' hover kind

[findleyr]

The 'Structured' hover kind does not serve human readable hover content. Rather, it serves JSON describing the hover.
https://github.com/golang/tools/blob/master/gopls/doc/settings.md#hoverkind-enum

gopls should conform to the semantics of the LSP: hover is intended to be human readable. If we want to delegate hover presentation to the client, we must by definition have a thick client, in which case the client can just use a separate command via workspace/executeCommand. By analogy, tsserver has a command for structured hover info: https://github.com/microsoft/TypeScript/blob/55f1248a2052eebdea6bc0e2eef754df89a44bf7/src/server/protocol.ts#L2015.

CC @adonovan

[adonovan]

I vaguely recall that the sole thick client of the Hover JSON output is one of the Vims. (The feature was added in the CL attached to #33352. Paging @myitcv for awareness.)

[myitcv]

Paging @myitcv for awareness.

Thanks, @adonovan - we're actually using what I believe the gopls default is in this space, "FullDocumentation":

https://github.com/govim/govim/blob/6280deb8b406332ed0c9f0eea59671d954b815ab/cmd/govim/gopls_client.go#L159

[adonovan]

[govim is] actually using what I believe the gopls default is in this space, "FullDocumentation":

Great, let's remove kind=structured then.

[gopherbot]

Change https://go.dev/cl/635226 mentions this issue: gopls/internal/settings: drop experimental hoverKind=Structured