feat: add support for *T pointers

tests/pointers.test

@@ -0,0 +1,16 @@
+[code]
+fn swap(a: *i32, b: *i32) {
+    let temp = *a;
+    *a = *b;
+    *b = temp;
+}
+
+fn main() -> i32 {
+    let x = 10;
+    let y = 20;
+    swap(&x, &y);
+    return x - y; // 20 - 10 = 10
+}
+
+[expected_return_code]
+10