doc: add lambdas to sample file

doc/sample/Expressions.im

@@ -112,7 +112,8 @@ class Person
     $ exampleProperty | get => self::val, set => self::val = value.
 
     $ exampleProperty2 |
-        get => self::val.
+        get => [ ^self::val ],
+        set => [ :x | self::val = x ].
 
     $ exampleProperty3 | get => 42.
 
@@ -120,3 +121,14 @@ class Person
 
     $ exampleProperty5 (get)
 end
+
+j = [ cout put:'Hello!' ].
+k = [ :x :y | cout put:'Hello, {x}, {y}!' ].
+
+x > 2
+    if:[ cout put:'True' ]
+    else:[ cout put: 'False' ].
+
+0 to:100 step:2 do:[ :i | cout put:'Count: {i}' ].
+
+p1 test(param:'Hello' :'World').