minor typos (#386)
minor typos (#386)

* small typo

* small typo

* code and description is not same

* statements polishing

* statements polishing

* minor typo

* statements polishing

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor typo

* minor  typo

* minor typo

* minor typo

* minor typo

* minor typos

d2l-ai/d2l-zh,d2l-ai/d2l-zh,mli/gluon-tutorials-zh,mli/gluon-tutorials-zh,mli/gluon-tutorials-zh,d2l-ai/d2l-zh,mli/gluon-tutorials-zh