lsp: slow types diagnostics quick fixes

[kitsonk]

In order to reduce developer friction, the LSP could support surfacing slow type diagnostics directly in an IDE.

For example, the following slow type diagnostic could be made available:

error[missing-explicit-return-type]: missing explicit return type in the public API
   --> /Users/kitsonk/github/oak/application.ts:841:3
    | 
841 |   [Symbol.for("Deno.customInspect")](
    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this function is missing an explicit return type
    = hint: add an explicit return type to the function

  info: all functions in the public API must have an explicit return type
  docs: https://jsr.io/go/slow-type-missing-explicit-return-type

In addition, the lsp could make quick fixes available to extract the inferred type from tsc to resolve the diagnostic.

[dsherret]

Slowly getting there (ex. https://github.com/denoland/deno/pull/22615)

[alexgleason]

Is there a command besides deno publish you can run to show slow types?

[dsherret]

deno publish --dry-run or deno lint when there's a deno.json with "name", "verison", and "exports", in the config, or { "lint": { "rules": { "include": ["no-slow-types"] }}}