[3.12] GH-92584: Remove Installing Python Modules (Distutils version) (GH-108020) (#108062)

* [3.12] GH-92584: Remove Installing Python Modules (Distutils version) (GH-108020).
(cherry picked from commit fbb7cbc)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: AA-Turner

Doc/contents.rst

@@ -20,10 +20,3 @@
    bugs.rst
    copyright.rst
    license.rst
-
-.. to include legacy packaging docs in build
-
-.. toctree::
-   :hidden:
-
-   install/index.rst

Doc/extending/building.rst

@@ -45,6 +45,7 @@ See the *"Multiple modules in one library"* section in :pep:`489` for details.
 
 .. highlight:: c
 
+.. _install-index:
 .. _setuptools-index:
 
 Building C and C++ Extensions with setuptools