project: Fix LSP TextDocumentSyncCapability dynamic registration (#36234)

Closes #36213

Use `textDocument/didChange`
([docs](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_synchronization))
instead of `textDocument/synchronization`.

Release Notes:

- Fixed an issue where Dart projects were being formatted incorrectly by
the language server.
f8b0105258smit committed on 8/15/2025, 10:54:54 AM· committed by GitHubparent2a57b16
1 file changedLine totals unavailable