Fixed typos in example programs.

examples/ada/Max_Array.adb

@@ -12,4 +12,4 @@ procedure Max_Array is
     end Max_Array;
 begin
     null;
-end Max_Array;
+end Max_Array;

examples/ada/Sum.adb

@@ -14,4 +14,4 @@ procedure Sum is
     end Sum;
 begin
     null;
-end Sum;
+end Sum;

examples/ada/default.adb

@@ -9,9 +9,9 @@ begin
     return num**2;
 end Square;
 
--- Ada 2012 also provides Expressiion Functions 
+-- Ada 2012 also provides Expression Functions
 -- (http://www.ada-auth.org/standards/12rm/html/RM-6-8.html)
 -- as a short hand for functions whose body consists of a 
--- single return statement. Hhowever they cannot be used as a
+-- single return statement. However they cannot be used as a
 -- complication unit.
 -- function Square(num : Integer) return Integer is (num**2);