add numpy spec

README.md

@@ -4,12 +4,11 @@
 
 [Book website](http://numpy.d2l.ai/) | [STAT 157 Course at UC Berkeley, Spring 2019](http://courses.d2l.ai/berkeley-stat-157/index.html)
 
-This version is based on the classic `ndarray` interface.
-
+This is based on the NumPy interface.
 
 ## Contribute ([learn how](http://numpy.d2l.ai/chapter_appendix/how-to-contribute.html))
 
-This open source book has benefited from pedagogical suggestions, typo corrections, and other improvements from community contributors. Your help is valuable for making the book better for everyone. We will [acknowledge](https://www.d2l.ai/chapter_preface/preface.html#Acknowledgments) each D2L contributor in the book and send a free book (hard copy) to the **first 100 contributors** when it is published. 
+This open source book has benefited from pedagogical suggestions, typo corrections, and other improvements from community contributors. Your help is valuable for making the book better for everyone. We will [acknowledge](https://www.d2l.ai/chapter_preface/preface.html#Acknowledgments) each D2L contributor in the book and send a free book (hard copy) to the **first 100 contributors** when it is published.
 
 **Dear [D2L contributors](https://github.com/d2l-ai/d2l-en/graphs/contributors), please email your GitHub ID, name, and mailing address to [email protected]. Thanks.**
 
@@ -28,4 +27,3 @@ Please use the following bibtex entry to cite this book:
     year={2019}
 }
 ```
-