Fix small typo

Author: Husenap

_overviews/scala3-book/taste-vars-data-types.md

@@ -186,7 +186,7 @@ println(s"x.abs = ${x.abs}")   // prints "x.abs = 1"
 
 The `s` that you place before the string is just one possible interpolator.
 If you use an `f` instead of an `s`, you can use `printf`-style formatting syntax in the string.
-Furthermore, a string interpolator is a just special method and it is possible to define your own.
+Furthermore, a string interpolator is just a special method and it is possible to define your own.
 For instance, some database libraries define the very powerful `sql` interpolator.
 
 #### Multiline strings