lsp: Send client process ID in LSP initialize request (#43988)
Shuhei Kadowaki
created
Per the [LSP
specification](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#initializeParams),
the client should send its process ID to the language server so the
server can monitor the client process and shut itself down if the client
exits unexpectedly.
Release Notes:
- N/A