fix spelling mistake

tutorials/01-basics/logistic_regression/main.py

@@ -59,7 +59,7 @@ for epoch in range(num_epochs):
                    .format(epoch+1, num_epochs, i+1, total_step, loss.item()))
 
 # Test the model
-# In test phase, we don't need to compute gradients (for memory efficieny)
+# In test phase, we don't need to compute gradients (for memory efficiency)
 with torch.no_grad():
     correct = 0
     total = 0
@@ -73,4 +73,4 @@ with torch.no_grad():
     print('Accuracy of the model on the 10000 test images: {} %'.format(100 * correct / total))
 
 # Save the model checkpoint
-torch.save(model.state_dict(), 'model.ckpt')
+torch.save(model.state_dict(), 'model.ckpt')