Chapter attention mechanisms/transformer (#772)
Chapter attention mechanisms/transformer (#772)

* fix errors in 10.7. Transformer

* fix errors in 10.7.1. Model

* fix errors in 10.7.2. Positionwise Feed-Forward Networks

* fix errors in 10.7.4. Encoder

* fix errors in 10.7.5. Decoder

* fix errors in 10.7.6. Training
the end of fix errors in 10.7.

* fix errors in 10.7.1. Model

* fix errors in 10.7.2. Positionwise Feed-Forward Networks

* fix errors in 10.7.3. Residual Connection and Layer Normalization

* fix errors in 10.7.4. Encoder

* fix errors in 10.7.5. Decoder

* fix errors in 10.7.6. Training
the end of fix errors in 10.7.

* end of fix errors in 10.7. Transformer
d2l-ai/d2l-zh,mli/gluon-tutorials-zh,mli/gluon-tutorials-zh,mli/gluon-tutorials-zh,mli/gluon-tutorials-zh,d2l-ai/d2l-zh,d2l-ai/d2l-zh