Add a warning about the arena functions to Plinkin the Alchemist

[bobofwestoregonusa]

Plinkin's sending makes it sound like he's going to test potions or spells on you and not like an arena fight. This can lead to a very sudden death, especially to players who don't already know how the arena works. A warning  that you're about to enter the arena would be nice, or some actual indication that combat is about to take place. Currently he gives none of that and immediately starts casting spells.