Update README and API doc for Chipper announcement (#940)

Update README and API doc for Chipper model beta version announcement

README.md

@@ -33,11 +33,13 @@
   <p>API Announcement!</p>
 </h3>
 
-<p>While access to the hosted Unstructured API will remain free, API Keys will soon be required to make requests. To prevent any disruption, get yours <a href="https://www.unstructured.io/api-key/">here</a> now and start using it today!</p>
+We are thrilled to announce our newly launched [Unstructured API](https://unstructured-io.github.io/unstructured/api.html). While access to the hosted Unstructured API will remain free, API Keys will soon be required to make requests. To prevent disruption, get yours [here](https://www.unstructured.io/api-key/) now and start using it today! Check out the [readme](https://github.com/Unstructured-IO/unstructured-api#--) here to get started making API calls.</p>
 
-<p>Checkout the <a href="https://github.com/Unstructured-IO/unstructured-api#--">readme</a> here to get started making API calls.
-We'd love to hear your feedback, let us know how it goes in our
-  community slack. And stay tuned for improvements to both quality and performance!</p>
+#### :rocket: Beta Feature: Chipper Model
+
+We are releasing the beta version of our Chipper model to deliver superior performance when processing high-resolution, complex documents. To start using the Chipper model in your API request, you can utilize the `hi_res` strategy. Please refer to the documentation [here](https://unstructured-io.github.io/unstructured/api.html#strategies).
+
+As the Chipper model is in beta version, we welcome feedback and suggestions. For those interested in testing the Chipper model, we encourage you to connect with us on [Slack community](https://join.slack.com/t/unstructuredw-kbe4326/shared_invite/zt-1x7cgo0pg-PTptXWylzPQF9xZolzCnwQ).
 
 <h3 align="center">
   <p>Open-Source Pre-Processing Tools for Unstructured Data</p>

docs/source/api.rst

@@ -147,6 +147,25 @@ The ``ocr_only`` strategy runs the document through Tesseract for OCR. Currently
 
 For the best of all worlds, ``auto`` will determine when a page can be extracted using ``fast`` or ``ocr_only`` mode, otherwise, it will fall back to hi_res.
 
+Beta Version: ``hi_res`` Strategy with Chipper Model
+-----------------------------------------------------
+
+To use the ``hi_res`` strategy with **Chipper** model, pass the argument for ``hi_res_model_name`` as shown in the code block below.
+
+.. code:: shell
+
+ curl -X 'POST' \
+  'https://api.unstructured.io/general/v0/general' \
+  -H 'accept: application/json' \
+  -H 'Content-Type: multipart/form-data' \
+  -H 'unstructured-api-key: <YOUR API KEY>' \
+  -F 'strategy=hi_res' \
+  -F 'hi_res_model_name=chipper' \
+  -F 'files=@sample-docs/layout-parser-paper-fast.pdf' \
+  -F 'strategy=hi_res' \
+  | jq -C . | less -R
+
+*Please note that the Chipper model does not currently support the coordinates argument.*
 
 XML Tags
 =========