Allow both integer and string request IDs in LSP

[mprihoda]

Zed's LSP support expects request messages to have integer ID, Metals LSP uses string. According to specification, both is acceptable:

interface RequestMessage extends Message {

/**
 * The request id.
 */
id: integer | string;

...
This pull requests modifies the types and serialization/deserialization so that string IDs are accepted.

[SomeoneToIgnore]

Thank you for separating it out of the Scala PR, this seems quite a fundamental change indeed to have it mixed with the other ones.

I'm curious to know how Scala LSP is supposed to react to our integer IDs sent and mixed with the string ones?
I expect no issues as long as those are unique and there's no overlap with the server ones (that we do not ensure anyway now, so seems tolerable), but is it true?

[mprihoda]

I'm curious to know how Scala LSP is supposed to react to our integer IDs sent and mixed with the string ones?
I expect no issues as long as those are unique and there's no overlap with the server ones (that we do not ensure anyway now, so seems tolerable), but is it true?

Metals works just fine with the integer IDs generated by Zed, it returns the integer back correctly.

[SomeoneToIgnore]

Beautiful, thank you for finally making us spec-compliant on that front.

I see an odd CI error and wondering if you could rebase on a fresh main?
If that would not fix it, I'll just merge it since it seems unrelated, but let's be on a safe side.

[SomeoneToIgnore]

Yes, here's the commit we want to pull into: #7803

[mprihoda]

Rebased, and improved the commit messages while I've been at it.