26.1 Functions: three -> four advantages (#1565)

Very small issue.
Text says three advantages then lists four.
I believe 1e listed three.

functions.qmd

@@ -10,7 +10,7 @@ source("_common.R")
 
 One of the best ways to improve your reach as a data scientist is to write functions.
 Functions allow you to automate common tasks in a more powerful and general way than copy-and-pasting.
-Writing a function has three big advantages over using copy-and-paste:
+Writing a function has four big advantages over using copy-and-paste:
 
 1.  You can give a function an evocative name that makes your code easier to understand.