Add FAQ on imports

[mtomko]

This is to address the potential confusion with java.lang.IO

I did experiment with a third option:

import java.lang.IO as _

object Test {

  def test: IO[Unit] = ???

}

but empirically, this didn't actually work - for some reason scalac insisted that the problem was not a missing type but rather than IO doesn't take type parameters (implying that it was referring to java.lang.IO rather than cats.effect.IO. I think that's odd but it's more likely that the right solution is just to import cats.effect.IO directly anyway.

[durban]

Another option is a proper -release < 25 (or -java-output-version on dotty) scalac option. Of course, that's not applicable if one needs something from JDK 25.

[mtomko]

I'll note those options too. I don't know how long on the tooth we want to get for this potentially niche issue, though - presumably for the most part this will be useful only to beginners, as a seasoned Scala dev will recognize right away that the problem must be a conflicting definition.

[durban]

Sure, I've just wanted to mention it.