Some LSP servers, such as `ruby-lsp` (https://github.com/Shopify/ruby-lsp)
don't use `textDocument/publishDiagnostic` to publish diagnostics. Instead,
they expect the LSP client to poll and request diagnostics with
`textDocument/diagnostic`. It would be great if Eglot would support this
method of pulling diagnostics.

I first reported this on Github in the Eglot repo as a Discussion:
https://github.com/joaotavora/eglot/discussions/1290

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best,
Justin Talbott