Update introduction.md (#705)

I believe that documentation can be updated to say `colon` instead of `semi-colon`. https://docs.swift.org/swift-book/documentation/the-swift-programming-language/functions

exercises/concept/lasagna/.docs/introduction.md

@@ -78,7 +78,7 @@ In Swift, [functions][functions] are a chunk of code that performs a task.
 A function has a return type and can thereby be used as a value and be parsed as arguments to other functions.
 In Swift are functions defined using the `func` keyword followed by the name of the function, arguments separated by commas, and a return type.
 
-The arguments are defined by an argument label, a parameter name followed by a semi-colon and then a type.
+The arguments are defined by an argument label, a parameter name followed by a colon and then a type.
 The return type is defined by a `->` followed by the type of the return value.
 
 ```swift