New issue editor not restored correctly

[jrieken]

Testing #98019

• open and pin vscode.d.ts, vscode.proposed.d.ts, and NewIssue.md, open another file
• reload window
• select the 'N' editor
• an error about a missing file system provider happens (not sure if that's because of a missing activation event or because the event isn't fired)

[alexr00]

It looks like the file system provider is just registered too late in the extension. The extension already *-activates, but I can also add an onFileSystem activation if the editor looks for that. I'll also move the registration up.

[bpasero]

@alexr00 can you check if this reproduces independently from the editor being pinned, I would not expect that to have any impact.

[alexr00]

It is independent of pinning.

[lramos15]

There's no longer an error, but newIssue.md is blank after reloading the window. I'm not sure what the expected behavior is. I'm going to reopen this for now as I would still classify that as not restoring correctly, but feel free to close this if this was intended.

[alexr00]

It's intended, as the state of the repo may have changed since the file was created in VS Code.