The aircraft won't initiate a go around for windshear. It gives the crew a warning of windshear if it is encountered, or of windshear ahead if Predictive Windshear is fitted. The crew can make a decision baed on the information.
What you may be thinking of is Alpha Floor Protection. This is a function of the protection systems and it triggers if the speed is significantly below the Alpha Floor Protection speed which is computed by the Flight Augmentation Computer and is based on angle of attack. If it triggers, the AP/FDs will initiate TOGA and the thrust goes to TOGA regardless of the Thrust Lever angle. It can be disengaged by swtching off the FDs and/or disengaging the AP. However, the thurst goes into TOGA Lock and can only be disengaged by deselecting Autothrust.