Language status item doesn't appear when language mode is set

[karrtikr]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version: 1.64.0-insider (user setup)
• OS Version: Windows_NT x64 10.0.22518

Steps to Reproduce:

1. Create a untitled file.
2. Select a language mode.
3. Language status items for that language do not appear.
4. Open another untitled file and go back to the original file.
5. Language status items now start appearing.

Here's a GIF to describe the process:

This is currently a major blocker for us in adapting the new language status API: microsoft/vscode-python#18040, as we have a getting started experience where we teach the user to create an untitled file and then select an interpreter using the status bar, which will not be possible without this bug fix.

The bug is probably somewhere around

vscode/src/vs/workbench/api/common/extHostDocuments.ts

Lines 114 to 116 in 7ade5dd

	this._onDidRemoveDocument.fire(data.document);
	data._acceptLanguageId(newLanguageId);
	this._onDidAddDocument.fire(data.document);

where we miss to fire a language status item event when we set a language mode.

cc @isidorn