add description for models.list method

Author: zeke

README.md

@@ -201,6 +201,8 @@ const response = await replicate.models.get(model_owner, model_name);
 
 ### `replicate.models.list`
 
+Get a paginated list of all public models.
+
 ```js
 const response = await replicate.models.list();
 ```