Is it permissible to pray Salatul-Istikhara for marriage?

Marriage and other matters are addressed in the Istikhara hadith narrated by Al-Bukhari from Jabir (may Allah be pleased with him), who said: "The Messenger of Allah (peace and blessings of Allah be upon him) used to teach us Istikhara in all matters just as he would teach us a Surah from the Quran. He would say: 'If one of you is concerned about a matter, let him say...'" A specific hadith regarding marriage was narrated by Imam Ahmad and Al-Hakim from Abu Ayyub Al-Ansari, that the Messenger of Allah (peace and blessings of Allah be upon him) said to him: "Keep the proposal secret, then perform Wudu thoroughly, then pray what Allah has decreed for you, then praise and glorify your Lord, then say: 'O Allah, indeed You are able and I am not, and You know and I do not, and You are the Knower of the unseen. If You see that [mention her name] is good for me in my religion, my worldly life, and my Hereafter, then decree her for me. And if someone else is better for me than her in my religion, my worldly life, and my Hereafter, then decree her for me.'" In any case, marriage falls under the generality of his (peace and blessings of Allah be upon him) saying: "in a matter."