EOL feature problems don't update when the file is moved

[alexr00]

Testing #9020

1. Open an empty folder
2. Add a .devcontainer.json file:

{
	"image":"mcr.microsoft.com/devcontainers/typescript-node:0-20",
	"features": {
		"fish": "latest",
		"homebrew": "latest",
		"git": "latest"
	}
}

3. Note the 2 errors in the problems panel.
4. Make a folder .devcontainer in the explorer and drag .devcontainer.json into it
5. Now you have 4 errors, 2 of which are for a file that no longer exists

[rzhao271]

Still repros on v0.314.0

[rzhao271]

nvm it's good—the filename is updated properly
I get duplicate errors, though

[chrmarti]

Duplicate warnings are currently expected and tracked as #9024. Thanks.