extensions/extension-editing/src/packageDocumentHelper.ts/PackageDocument/provideCompletionItems
class PackageDocument:	public provideCompletionItems(position: vscode.Position, _token: vscode.CancellationToken): vscode.ProviderResult<vscode.CompletionItem[]> {
		const location = getLocation(this.document.getText(), this.document.offsetAt(position));

		if (location.path.length >= 2 && location.path[1] === 'configurationDefaults') {
			return this.provideLanguageOverridesCompletionItems(location, position);
		}

		return undefined;
	}