feat: toy tutorial chapter 4.

Signed-off-by: jackfiled <xcrenchangjun@outlook.com>

examples/multiply_transpose.hello

@@ -16,11 +16,5 @@ def main() {
   # reuse the previously specialized and inferred version and return <3, 2>.
   var d = multiply_transpose(b, a);
 
-  # A new call with <3, 2> (instead of <2, 3>) for both dimensions will
-  # trigger another specialization of `multiply_transpose`.
-  var e = multiply_transpose(c, d);
-
-  # Finally, calling into `multiply_transpose` with incompatible shapes
-  # (<2, 3> and <3, 2>) will trigger a shape inference error.
-  var f = multiply_transpose(a, c);
+  print(d);
 }