fix(amazonq): duplicated onDidSaveTextDocument notification

[jngyuamz]

Problem

• Server could not receive onDidSaveTextDocument event from VSCode
• Servers receive duplicated onDidSaveTextDocument events.

Solution

• According to VSCode spec, textDocument/didSave is the correct name for this event

Update

• After this change: fix: onDidSaveTextDocument routing language-server-runtimes#590, all the servers are able to receive the event from the TextDocumentConnection, so we don't need to let VSCode send the didSave event to client, otherwise, it will cause duplicated events on server side.

---

• Treat all work as PUBLIC. Private feature/x branches will not be squash-merged at release time.
• Your code changes must meet the guidelines in CONTRIBUTING.md.
• License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.
• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.

[leigaol]

1/ Can there be any other duplicate events?

2. If user is using old vsc plugin with new Flare LSP, what happens? I assume the duplicate will exist

[jngyuamz]

1/ Can there be any other duplicate events?

There are 4 events from TextDocObserver: onDidOpenTextDocument, onDidCloseTextDocument, onWillSaveTextDocument, onDidSaveTextDocument, only onDidSaveTextDocument has duplicated events.

If user is using old vsc plugin with new Flare LSP, what happens? I assume the duplicate will exist

No, because this client.sendNotification('workspace/didSaveTextDocument') actually never worked, because VS Code doesn't have this method name 'workspace/didSaveTextDocument'. It should be textDocument/didSave. Duplicated events only happened in my first revision of this PR, I changed workspace/didSaveTextDocument to textDocument/didSave