* [Docs] Update weight initialization in cnn.md
* Update cnn.md
* [Docs] Update weight initialization in cnn.md
* [Docs] Update weight initialization in cnn.md
* [Docs] Update weight initialization in cnn.md
* [Docs] Update weight initialization in cnn.md
* [Docs] Update weight initialization in cnn.md
* modify docs according to comments
* modify docs for weight init according to the comment
* change init_weight() to init_weights()
* modify according to comment