minor addition in Q.index() usage description.
minor addition in Q.index() usage description.

NerdWalletOSS/Q,NerdWalletOSS/Q,NerdWalletOSS/Q,NerdWalletOSS/Q,NerdWalletOSS/Q,NerdWalletOSS/Q,NerdWalletOSS/Q,NerdWalletOSS/Q