What is the ruling on the prostration of forgetfulness (sujūd al-sahw)? And what are the evidences for that?

Scholars have differed concerning the ruling on the prostration of forgetfulness (sujud as-sahw). The Malikis and Shafi'is held that it is Sunnah, citing the Prophet's (peace and blessings be upon him) hadith: "The rak'ah was supererogatory, and the two prostrations (of forgetfulness) are for it." As for the Hanafis, they stated its obligation, and this is the correct view according to them. The Hanbalis said it is obligatory for what intentionally invalidates the prayer, such as an addition or omission. It is recommended according to them for one who unintentionally omits an obligatory act, and permissible for one who makes a grammatical error that distorts the meaning due to forgetfulness or ignorance.