Update functions.md

basarat · web-flow · commit c52ec8efe337 · 2016-07-21T07:58:12.000+10:00
diff --git a/docs/types/functions.md b/docs/types/functions.md
@@ -1,3 +1,8 @@
+* [Parameter Annotations](#parameter-annotations)
+* [Return Type Annotation](#return-type-annotation)
+* [Optional Parameters](#optional-parameters)
+* [Overloading](#overloading)
+
 ## Functions
 The TypeScript type system pays a lot of love to functions, after all they are the core building block of a composable system.
 
