added generics ast

examples/generics.bl

@@ -2,11 +2,11 @@ type MyTrait trait {}
 
 type Pair[K, V: MyTrait] struct {
     k: K,
-    v: V,
+    v: V
 }
 
 type Value struct {
-    value: i64,
+    value: i64
 }
 
 impl MyTrait for Value {}
@@ -21,7 +21,7 @@ impl [K, V: MyTrait] Pair[K, V] {
 fn main(): i64 {
     let a = Pair[i64, Value]{
         k: 4,
-        v: Value{value: 6},
+        v: Value{value: 6}
     };
     return a.get_value[i64](999).value;
 }