src/vs/platform/terminal/common/capabilities/terminalCapabilityStore.ts/TerminalCapabilityStoreMultiplexer/add
class TerminalCapabilityStoreMultiplexer:	add(store: ITerminalCapabilityStore) {
		this._stores.push(store);
		for (const capability of store.items) {
			this._onDidAddCapability.fire(capability);
		}
		store.onDidAddCapability(e => this._onDidAddCapability.fire(e));
		store.onDidRemoveCapability(e => this._onDidRemoveCapability.fire(e));
	}