Reports usages of alphanumeric definitions without `infix` modifier as infix operator.

• "Wrap in backticks" quick-fix adds ` symbols around calls.
• "Convert from infix expression" quick-fix converts infix call to method syntax .method(...).
• "Convert from infix type" quick-fix converts infix type to prefix syntax Type[...].
• "Convert from infix pattern" quick-fix converts infix pattern to prefix syntax pattern(...).

Example:

  class C:
    def op(x: Int): Int = ???
  type Or[X, Y]
  case class Pair[T](x: T, y: T)

  val c = C()
  val p = Pair(1, 2)

  c op 2
  val or: Int Or String = ???
  val _ Pair _ = p

After the "Wrap in backticks" quick-fix is applied:

  class C:
    def op(x: Int): Int = ???
  type Or[X, Y]
  case class Pair[T](x: T, y: T)

  val c = C()
  val p = Pair(1, 2)

  c `op` 2
  val or: Int `Or` String = ???
  val _ `Pair` _ = p

After the "Convert from infix expression" quick-fix is applied:

  class C:
    def op(x: Int): Int = ???
  type Or[X, Y]
  case class Pair[T](x: T, y: T)

  val c = C()
  val p = Pair(1, 2)

  c.op(2)
  val or: Int Or String = ???
  val _ Pair _ = p

After the "Convert from infix type" quick-fix is applied:

  class C:
    def op(x: Int): Int = ???
  type Or[X, Y]
  case class Pair[T](x: T, y: T)

  val c = C()
  val p = Pair(1, 2)

  c op 2
  val or: Or[Int, String] = ???
  val _ Pair _ = p

After the "Convert from infix pattern" quick-fix is applied:

  class C:
    def op(x: Int): Int = ???
  type Or[X, Y]
  case class Pair[T](x: T, y: T)

  val c = C()
  val p = Pair(1, 2)

  c op 2
  val or: Int Or String = ???
  val Pair(_, _) = p