Update writing_your_own_callbacks.py (#21671)

Fix `AttributeError: `np.Inf` was removed in the NumPy 2.0 release. Use `np.inf` instead.` exception

Author: TRNWWZ

guides/writing_your_own_callbacks.py

@@ -333,7 +333,7 @@ def on_train_begin(self, logs=None):
         # The epoch the training stops at.
         self.stopped_epoch = 0
         # Initialize the best as infinity.
-        self.best = np.Inf
+        self.best = np.inf
 
     def on_epoch_end(self, epoch, logs=None):
         current = logs.get("loss")