Add include for installing Python.

Add install Buildout as a pre-requisite.

Author: stevepiercy

docs/_inc/_install-python-plone61.md

@@ -0,0 +1,8 @@
+Installing Python is beyond the scope of this documentation.
+However, it is recommended to use a Python version manager, {term}`pyenv`, that allows you to install multiple versions of Python on your development environment without destroying your system's Python.
+% TODO: uncomment this line after upgrading to plone-sphinx-theme and latest Sphinx which supports replacements inside includes.
+% Plone requires Python version {SUPPORTED_PYTHON_VERSIONS_PLONE61}.
+
+Plone 6.0 requires Python version 3.8, 3.9, 3.10, 3.11, or 3.12.
+
+Plone 6.1 requires Python version 3.10, 3.11, or 3.12.

docs/admin-guide/install-buildout.md

@@ -22,16 +22,23 @@ For other installation options, see {ref}`get-started-install-label`.
 
 (install-buildout-prerequisites)=
 
-## Prerequisites
+## Prerequisites for installation
 
-- Python (SUPPORTED_PYTHON_VERSIONS_PLONE61)
+- For Plone 6.0, Python {SUPPORTED_PYTHON_VERSIONS_PLONE60}
+- For Plone 6.1, Python {SUPPORTED_PYTHON_VERSIONS_PLONE61}
+- Buildout
 
-On Debian-based Linux systems you can install Python with the following command:
 
-```shell
-sudo apt install python3.12 python3.12-dev python3.12-venv
+### Python
+
+```{include} /_inc/_install-python-plone61.md
 ```
 
+### Buildout
+
+See [Getting started with Buildout](http://www.buildout.org/en/latest/getting-started.html).
+
+
 ## Installation
 
 Select a directory of your choice: