Mujahideen just the plural form of mujahid: a person who engages in Jihad. It is not a specific group. The term applies equally well to the Taliban as the many other groups that operated in Afghanistan.
The Taliban did not in any case organize until after infighting broke out again among those groups, and the Taliban's growth came in large part exactly because these groups were far more disunited at the point the Taliban was rising than during the war against the Soviets.