publish variadic functions. also, spelling

examples/variadic-functions/variadic-functions.sh

@@ -0,0 +1,7 @@
+$ go run variadic-functions.go 
+[1 2] 3
+[1 2 3] 6
+[1 2 3 4] 10
+
+# Another key aspect of functions in Go is their ability
+# to form closures, which we'll look at next.