doc: add more complex expressions to sample file

doc/sample/Expressions.im

@@ -1,4 +1,4 @@
-
+/*
 y = 1 + 2 * 3 / 4 * 5 - 6 + 7 multiplyBy:2.
 z = w = 2 + 3 multiplyBy:2.
 x = (((1 + 2 * 3) multiplyBy:3) add: 5) + 2.
@@ -23,4 +23,11 @@ x = OrderedCollection new
 
 age = Person new(name:"John Doe" age:34)
     setAge:144 inUnit:"months";
-    ageInMonths.
+    ageInMonths.
+*/
+
+--x = 5.
+--q = 10 if x > 2.
+--q = if x > 2 then 10 else 20 end.
+
+cout put:5 multiply(by:5 add:2).