!8347 mode_warmuplr_docs

From: @bai-yangfan
Reviewed-by: @sanjaychan,@kingxian
Signed-off-by: @sanjaychan

mindspore/nn/learning_rate_schedule.py

@@ -377,7 +377,7 @@ class WarmUpLR(LearningRateSchedule):
     Examples:
         >>> learning_rate = 0.1
         >>> warmup_steps = 2
-        >>> global_step = Tenosr(2, mstype.int32)
+        >>> global_step = Tensor(2, mstype.int32)
         >>> warmup_lr = WarmUpLR(learning_rate, warmup_steps)
         >>> warmup_lr(global_step)
     """