Custom editor webviews should not be recreated on rename

From #85991 **Repo** 1. Using the `.abc` editor from https://github.com/mjbvz/vscode-experimental-webview-editor-extension/ 1. Create a file called `x.abc`. Open it 1. With the custom editor for `x.abc` still open, rename `x.abc` file to `y.abc` in the VS Code file explorer **Bug** Notice that the editor's webview is destroyed and then recreated. It would be preferable in this webview were kept alive across the rename (although perhaps only if the editor capabilities implement a `rename` method) You can better confirm this by putting some sort of state into the webview, such as a script consisting of: ```js let i = 0; setInterval(() => console.log(++i), 1000); ````