The official style guide says the opposite:

    Avoid! Despite the degree to which Scala facilitates
    this area of API design, the definition of methods with
    symbolic names should not be undertaken lightly,
    particularly when the symbols itself are non-standard 
    (for example, >>#>>). As a general rule, symbolic 
    method names have two valid use-cases:
    
      Domain-specific languages (e.g. actor1 ! Msg)
      Logically mathematical operations (e.g. a + b or c :: d)
    
    The definition of methods with symbolic names should be
    considered an advanced feature in Scala, to be used only 
    by those most well-versed in its pitfalls. Without care, 
    excessive use of symbolic method names can easily 
    transform even the simplest code into symbolic soup.

And searching ... well, every symbolic method name has a searchable string embedded in ScalaDoc.

Additionally, you can also click on the index and get every symbolic method with the place where it is defined.

I don't really understand what's so hard about that ...