Merge pull request #57 from atomscale-ai/enhancement/doc_update

Fix API key env text

Author: munrojm

docs/index.rst

@@ -42,9 +42,9 @@ Installation
 
   pip install atomscale
 
-Set the ``AS_API_KEY`` and (optional) ``AS_API_ENDPOINT`` environment variables
-before creating a :class:`~atomscale.client.Client`, or pass them directly when
-constructing the client in your scripts.
+Much of the functionality of the package requires an API key. It can be provided using
+the ``AS_API_KEY`` environment variable before creating a :class:`~atomscale.client.Client`,
+or passed in directly when constructing the client in your code.
 
 .. note::