Added separate links to stable/latest/3.6 copies of the offline documentation

Author: pizzafaceopossum

index.rst

@@ -51,20 +51,11 @@ into your language, or talk to us on the ``#documentation`` channel on the
 Offline documentation
 ---------------------
 
-To browse the documentation offline, you can use the mirror of the documentation
-hosted on `DevDocs <https://devdocs.io/godot/>`__. To enable offline browsing on
-DevDocs, you need to:
-
-- Click the three dots in the top-left corner, choose **Preferences**.
-- Enable the desired version of the Godot documentation by checking the box
-  next to it in the sidebar.
-- Click the three dots in the top-left corner, choose **Offline data**.
-- Click the **Install** link next to the Godot documentation.
-
-You can also `download an HTML copy <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-html-master.zip>`__
-for offline reading (updated every Monday). Extract the ZIP archive then open
+To browse the documentation offline, you can download an HTML copy (updated every Monday): `stable <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-html-stable.zip>`__, `latest <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-html-master.zip>`__, `3.6 <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-html-3.6.zip>`__. Extract the ZIP archive then open
 the top-level ``index.html`` in a web browser.
 
+For mobile devices or e-readers, you can also download an ePub copy (updated every Monday): `stable <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-epub-stable.zip>`__, `latest <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-epub-master.zip>`__, `3.6 <https://nightly.link/godotengine/godot-docs/workflows/build_offline_docs/master/godot-docs-epub-3.6.zip>`__. Extract the ZIP archive then open
+the ``GodotEngine.epub`` file in an e-book reader application.
 
 .. Below is the main table-of-content tree of the documentation website.
    It is hidden on the page itself, but it makes up the sidebar for navigation.