Fix doctest normalize_by_update_norm

PiperOrigin-RevId: 650580171

optax/_src/transform.py

@@ -1504,15 +1504,14 @@ def normalize_by_update_norm(
     >>> def f(x): return jnp.sum(x ** 2)  # simple quadratic function
     >>> solver = optax.normalize_by_update_norm(scale_factor=-1.0)
     >>> params = jnp.array([1., 2., 3.])
-    >>> print('Objective function: ', f(params))
-    Objective function:  14.0
+    >>> print('Objective function:', f(params))
+    Objective function: 14.0
     >>> opt_state = solver.init(params)
     >>> for _ in range(5):
     ...  grad = jax.grad(f)(params)
     ...  updates, opt_state = solver.update(grad, opt_state, params)
     ...  params = optax.apply_updates(params, updates)
     ...  print('Objective function: {:.2E}'.format(f(params)))
-    Objective function:  14.0
     Objective function: 7.52E+00
     Objective function: 3.03E+00
     Objective function: 5.50E-01