[WIP] Fix crash for signature help in arrow function parameters

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Crash for signature help in arrow function parameters</issue_title> <issue_description>```ts const comparers: Array<(a: any, b: any) => boolean> = [];

comparers.push((a,/**/ b) => true);

Somehow this brings down the whole server without sending back a proper stack trace.</issue_description>

<agent_instructions>Feel free to modify `recover` in `lsp/server.go` to dig into a potential stack trace.</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

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• Fixes microsoft/typescript-go#2336

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