extensions/references-view/src/tree.ts/TreeInputHistory/add
class TreeInputHistory:	async add(input: SymbolTreeInput<unknown>) {

		const doc = await vscode.workspace.openTextDocument(input.location.uri);

		const anchor = new WordAnchor(doc, input.location.range.start);
		const range = doc.getWordRangeAtPosition(input.location.range.start) ?? doc.getWordRangeAtPosition(input.location.range.start, /[^\s]+/);
		const word = range ? doc.getText(range) : '???';

		const item = new HistoryItem(JSON.stringify([range?.start ?? input.location.range.start, input.location.uri, input.title]), word, anchor, input);
		// use filo-ordering of native maps
		this._inputs.delete(item.key);
		this._inputs.set(item.key, item);
		this._ctxHasHistory.set(true);
	}