Move docs to a topic

Author: pfmoore

docs/html/topics/index.md

@@ -18,4 +18,5 @@ local-project-installs
 repeatable-installs
 secure-installs
 vcs-support
+python-option
 ```

docs/html/topics/python-option.md

@@ -0,0 +1,38 @@
+# Managing a different Python interpreter
+
+
+Occasionally, you may want to use pip to manage a Python installation other than
+the one pip is installed into. In this case, you can use the `--python` option
+to specify the interpreter you want to manage. This option can take one of three
+values:
+
+1. The path to a Python executable.
+2. The path to a virtual environment.
+3. Either "py" or "python", referring to the currently active Python interpreter.
+
+In all 3 cases, pip will run exactly as if it had been invoked from that Python
+environment.
+
+One example of where this might be useful is to manage a virtual environment
+that does not have pip installed.
+
+````{tab} Unix/macOS
+```{code-block} console
+$ python -m venv .venv --without-pip
+$ python -m pip --python .venv install SomePackage
+[...]
+Successfully installed SomePackage
+```
+````
+````{tab} Windows
+```{code-block} console
+C:\> py -m venv .venv --without-pip
+C:\> py -m pip --python .venv install SomePackage
+[...]
+Successfully installed SomePackage
+```
+````
+
+You could also use `--python .venv/bin/python` (or on Windows,
+`--python .venv\Scripts\python.exe`) if you wanted to be explicit, but the
+virtual environment name is shorter and works exactly the same.

docs/html/user_guide.rst

@@ -782,49 +782,6 @@ This is now covered in :doc:`../topics/repeatable-installs`.
 
 This is now covered in :doc:`../topics/dependency-resolution`.
 
-.. _`Managing a different Python interpreter`:
-
-Managing a different Python interpreter
-=======================================
-
-Occasionally, you may want to use pip to manage a Python installation other than
-the one pip is installed into. In this case, you can use the ``--python`` option
-to specify the interpreter you want to manage. This option can take one of three
-values:
-
-#. The path to a Python executable.
-#. The path to a virtual environment.
-#. Either "py" or "python", referring to the currently active Python interpreter.
-
-In all 3 cases, pip will run exactly as if it had been invoked from that Python
-environment.
-
-One example of where this might be useful is to manage a virtual environment
-that does not have pip installed.
-
-.. tab:: Unix/macOS
-
-   .. code-block:: console
-
-      $ python -m venv .venv --without-pip
-      $ python -m pip --python .venv install SomePackage
-      [...]
-      Successfully installed SomePackage
-
-.. tab:: Windows
-
-   .. code-block:: console
-
-      C:\> py -m venv .venv --without-pip
-      C:\> py -m pip --python .venv install SomePackage
-      [...]
-      Successfully installed SomePackage
-
-You could also use ``--python .venv/bin/python`` (or on Windows,
-``--python .venv\Scripts\python.exe``) if you wanted to be explicit, but the
-virtual environment name is shorter and works exactly the same.
-
-
 .. _`Using pip from your program`:
 
 Using pip from your program