Editorial change: adding function declaration

Author: gusthoff

content/courses/intro-to-ada/chapters/subprograms.rst

@@ -215,6 +215,9 @@ to explicitly store it in a local variable.
 .. code:: ada compile_button project=Courses.Intro_To_Ada.Subprograms.Quadruple
     :class: ada-expect-compile-error
 
+    function Quadruple (I : Integer)
+                        return Integer;
+
     function Quadruple (I : Integer)
                         return Integer is