src/vs/editor/common/config/editorConfigurationSchema.ts/getEditorConfigurationKeys
function getEditorConfigurationKeys(): { [key: string]: boolean } {
	if (cachedEditorConfigurationKeys === null) {
		cachedEditorConfigurationKeys = <{ [key: string]: boolean }>Object.create(null);
		Object.keys(editorConfiguration.properties!).forEach((prop) => {
			cachedEditorConfigurationKeys![prop] = true;
		});
	}
	return cachedEditorConfigurationKeys;
}