Update implicit-conversions.md (#2674)

* Update implicit-conversions.md

I'm not sure if it is intentional, but the Tour-of-Scala documentation does not mention how to bring implicit conversions into scope. In fact, that information is a bit hard to find anywhere else, so I thought I'll propose to add it here?

* Update _tour/implicit-conversions.md from suggestion

Co-authored-by: Jamie Thompson <bishbashboshjt@gmail.com>

* Update implicit-conversions.md

Improved Scala 3 description. Thanks for all the suggestions!

* Fix import in _tour/implicit-conversions.md

Co-authored-by: Jamie Thompson <bishbashboshjt@gmail.com>

* describe Scala 2 implicit conversion in companion object

* Remove mdoc from Scala 3 example

* Update _tour/implicit-conversions.md

* Update _tour/implicit-conversions.md

* Remove mdoc from Scala 2 example as well

Sorry for wasting your time, next time, I'll install the toolchain.

* merge section "How are implicit conversions selected?"

Co-authored-by: Jamie Thompson <bishbashboshjt@gmail.com>

Author: oliver-brm

_tour/implicit-conversions.md

@@ -38,9 +38,69 @@ In the second case, a conversion `c` is searched for, which is applicable to `e`
 
 An example is to compare two strings `"foo" < "bar"`. In this case, `String` has no member `<`, so the implicit conversion `Predef.augmentString("foo") < "bar"` is inserted. (`scala.Predef` is automatically imported into all Scala programs.)
 
-### How are implicit conversions selected?
+### How are implicit conversions brought into scope? ###
 
-See this [Scala FAQ Answer](https://docs.scala-lang.org/tutorials/FAQ/index.html#where-does-scala-look-for-implicits).
+{% tabs implicit-conversion-scope class=tabs-scala-version %}
+{% tab 'Scala 2' %}
+In Scala 2, an implicit conversion is brought into scope by importing from the object that defined it, (e.g. `Conversions` in this case). If the implicit conversion is in the companion object of the argument type, (e.g. `Student` in this case), then no import is necessary.
+
+```scala
+import scala.language.implicitConversions // required to define an implicit conversion
+
+case class Student(name: String)
+object Student {
+  implicit def fromStudentToInt(student: Student): Int = student.name.length
+}
+  
+object Conversions {
+  implicit def fromStringToStudent(name: String): Student = Student(name)
+}
+
+import Conversions._
+object Usage {
+  def main(args: Array[String]) = {
+    val reginald: Student = "Reginald" // applies the conversion Conversions.fromStringToStudent
+    println(reginald + 2)              // applies the conversion Student.fromStudentToInt
+  }
+}
+```
+{% endtab %}
+{% tab 'Scala 3' %}
+In Scala 3, an implicit conversion is brought into scope by either importing `given` or the named conversion from the object that defined it, (e.g. `Conversions` in this case). 
+
+Note that as of Scala 3, implicit conversions cannot be brought into scope anymore by means of a wildcard import (`*`). 
+
+Given the example:
+
+```scala
+case class Student(name: String):
+  def printName: Unit = println(name)
+object Student:
+  given Conversion[Student, Int] = _.name.length
+  
+object Conversions:
+  given fromStringToStudent: Conversion[String, Student] = Student(_)
+```
+
+The following imports would bring the `Conversion[String, Student]` into scope:
+  - `import Conversions.given`
+  - `import Conversions.{given Conversion[String, Student]}`
+  - `import Conversions.fromStringToStudent`
+
+If the implicit conversion is in the companion object of the argument type, (e.g. `Student` in this case), then no import is necessary.
+
+```scala
+import Conversions.given
+object Usage:
+  @main def run =
+    val reginald: Student = "Reginald" // applies the Conversion[String, Student]
+    println(reginald + 2)              // applies the Conversion[Student, Int]
+```
+{% endtab %}
+{% endtabs %}
+
+Further reading: 
+  - [Where does Scala look for implicits? (on StackOverflow)](https://docs.scala-lang.org/tutorials/FAQ/index.html#where-does-scala-look-for-implicits).
 
 ### Beware the power of implicit conversions