Merge pull request #2097 from alvyjudy/improve-doc

doc overhaul step 1: simplify index and group deprecated files

changelog.d/2097.doc.rst

+doc: simplify index and group deprecated files

docs/deprecated/index.txt

+======================================================
+Guides on backward compatibility & deprecated practice
+======================================================
+
+``Setuptools`` has undergone tremendous changes since its first debut. As its
+development continues to roll forward, many of the practice and mechanisms it
+had established are now considered deprecated. But they still remain relevant
+as a plethora of libraries continue to depend on them. Many people also find
+it necessary to equip themselves with the knowledge to better support backward
+compatibility. This guide aims to provide the essential information for such
+objectives.
+
+.. toctree::
+    :maxdepth: 1
+
+    python3
+    python_eggs
+    easy_install
+

docs/index.txt

@@ -14,12 +14,8 @@ designed to facilitate packaging Python projects, where packaging includes:
 Documentation content:
 
 .. toctree::
-   :maxdepth: 2
+   :maxdepth: 1
 
-   setuptools
-   pkg_resources
-   python3
-   development
-   roadmap
-   Deprecated: Easy Install <easy_install>
-   history
+   User guide <setuptools>
+   Development guide <development>
+   Backward compatibility & deprecated practice <deprecated/index>