editor: support 'close on file delete' preference

[vince-fugnitto]

Feature Description:

The goal is to support the close on file delete preference similarly to vscode to control the behavior when an editor's underlying resource is deleted or renamed.

theia/packages/filesystem/src/browser/filesystem-frontend-contribution.ts

Lines 262 to 284 in 632a67a

	protected async updateWidgets(event: FileChangesEvent): Promise<void> {
	if (!event.gotDeleted() && !event.gotAdded()) {
	return;
	}
	// eslint-disable-next-line @typescript-eslint/no-explicit-any
	const pending: Promise<any>[] = [];
	const dirty = new Set<string>();
	const toClose = new Map<string, NavigatableWidget[]>();
	for (const [uri, widget] of NavigatableWidget.get(this.shell.widgets)) {
	this.updateWidget(uri, widget, event, { dirty, toClose });
	}
	for (const [uriString, widgets] of toClose.entries()) {
	if (!dirty.has(uriString)) {
	for (const widget of widgets) {
	widget.close();
	pending.push(waitForClosed(widget));
	}
	}
	}
	await Promise.all(pending);
	}

theia/packages/filesystem/src/browser/filesystem-frontend-contribution.ts

Lines 285 to 307 in 632a67a

	protected updateWidget(uri: URI, widget: NavigatableWidget, event: FileChangesEvent, { dirty, toClose }: {
	dirty: Set<string>;
	toClose: Map<string, NavigatableWidget[]>
	}): void {
	const label = widget.title.label;
	const deleted = label.endsWith(this.deletedSuffix);
	if (event.contains(uri, FileChangeType.DELETED)) {
	const uriString = uri.toString();
	if (Saveable.isDirty(widget)) {
	if (!deleted) {
	widget.title.label += this.deletedSuffix;
	}
	dirty.add(uriString);
	}
	const widgets = toClose.get(uriString) || [];
	widgets.push(widget);
	toClose.set(uriString, widgets);
	} else if (event.contains(uri, FileChangeType.ADDED)) {
	if (deleted) {
	widget.title.label = widget.title.label.substr(0, label.length - this.deletedSuffix.length);
	}
	}
	}

Steps to Reproduce:

1. start the application and open a file (ex: readme.md).
2. delete the file on the filesystem.
3. the application currently closes the editor.