Small buff to Xerath

In lieu of an update to give him a modern passive, Xerath should get the same amount of mana from attacking minions as champions if the attack kills the minion. It'd allow him to stay at his preferred range for longer, rather than have to get within AA range for more mana.

Though really he and Lissandra are both in need of modern passives, considering the addition of 400 mana to the must-start item on mages made it so that these passives are more of a crutch than a benefit. Their abilities have higher costs to compensate even though they both buy items that grant mana first. And the passive of Athene's was moved onto a mastery of the same strength.

For a similar case, Veigar had his passive modernized by increasing its stacking ability and removing the mana regen.

So mana regen/ saving passives are long since outdated. It's just a few of Riot's less favored champions like Liss, Xerath, and Nunu who have been left to gather dust.