doc: fix minor typo
## Implementing your assets in python
-To help you implement your assets in Python, please have a look to the [Substra Tools](https://github.com/SubstraFoundation/substra-tools).
+To help you implement your assets in Python, please take a look at the [Substra Tools](https://github.com/SubstraFoundation/substra-tools).
## Learning about the Substra platform
