Support window/progress message

[fredemmott]

FB extension.

Signature here: https://github.com/facebook/hhvm/blob/master/hphp/hack/src/utils/lsp.ml#L850

Efforts to standardize this at microsoft/language-server-protocol#245 and microsoft/language-server-protocol#511

[PranayAgarwal]

What is the best way to get progress messages from the language server? Any current use case?

[fredemmott]

If they're in clientcapabilities, they should be pushed.

I believe that Hack will push them when initializing if it's not already running; if supported, HHAST could also push them for the whole-repo lint

[mroch]

@fredemmott updated permalink: https://github.com/facebook/hhvm/blob/0c4c1b966bec9cae74d9d35d13ffc93c449fa00a/hphp/hack/src/utils/lsp/lsp.ml#L1007

[PranayAgarwal]

I updated the initialize request to send over the following (in client capabilities):

"workspace": { ... },
"textDocument": { ... },
"window": {
    "status": true,
    "progress": true
}

but still don't get any of those requests from the language server. Anything else I should be doing?