These symbols are part of the definition of the Applicative type class in Haskell http://hackage.haskell.org/package/base-4.11.1.0/docs/Contro...
try googling < or "scala <*"...
I've had a junior dev ask me what kind of strange multiplication thing was going on in our C code base. If you don't even know about pointers, maybe you're not "junior" yet and should learn some more.
Symbols are fine as long as they're alias names for fully written out names.
I think Scala will support such an IDE feature with an @alias annotation in the future. (I saw that idea on a slide in a talk of M. Odersky some time ago but actually don't know the current status).