Update README.md

Author: RannelT

scala-core-modules/scala-strings-2/README.md

@@ -5,3 +5,4 @@ This module contains articles about Scala's Strings.
 ### Relevant Articles:
 -  [How to Check if a String Is Null or Empty in Scala](https://www.baeldung.com/scala/string-test-null-empty)
 -  [Convert From Camel Case to Snake Case in Scala](https://www.baeldung.com/scala/camel-snake-case-automatic-conversion)
+-  [Convert Multiple Spaces Into a Single Space in Scala](https://www.baeldung.com/scala/multiple-spaces-to-single-space)