Update intro-to-generics.md (quii#431)

Correct a typo:
A function that takes generic aguments
To:
A function that takes generic arguments

intro-to-generics.md

@@ -6,7 +6,7 @@ However, there are ways to experiment with the upcoming implementation using the
 
 This chapter will give you an introduction to generics, dispel reservations you may have about them and, give you an idea how to simplify some of your code in the future. After reading this you'll know how to write:
 
-- A function that takes generic aguments
+- A function that takes generic arguments
 - A generic data-structure
 
 ## Setting up the playground