Scala tour add explanation for Scala 3 class instantiation (#2656)

* Add explanation for Scala 3 class instantiation

* Add link to "universal apply methods" Scala reference

Co-authored-by: Jamie Thompson <[email protected]>

Co-authored-by: Majid Hajiheidari <[email protected]>
Co-authored-by: Jamie Thompson <[email protected]>

Author: 3 people

_tour/basics.md

@@ -272,7 +272,7 @@ class Greeter(prefix: String, suffix: String):
 
 The return type of the method `greet` is `Unit`, which signifies that there is nothing meaningful to return. It is used similarly to `void` in Java and C. (A difference is that, because every Scala expression must have some value, there is actually a singleton value of type Unit, written (). It carries no information.)
 
-You can make an instance of a class with the `new` keyword:
+In Scala 2 you can make an instance of a class with the `new` keyword. In Scala 3, however, the `new` keyword is not needed thanks to [universal apply methods](https://docs.scala-lang.org/scala3/reference/other-new-features/creator-applications.html):
 
 {% tabs greeter-usage class=tabs-scala-version %}