Add repo configuration

Signed-off-by: tldahlgren <35777542+tldahlgren@users.noreply.github.com>

Author: tldahlgren

outputs/packaging/repo-config.out

@@ -0,0 +1,6 @@
+$ spack config get repos
+repos:
+  tutorial: /home/spack7/repos/spack_repo/tutorial
+  builtin:
+    git: https://github.com/spack/spack-packages.git
+    branch: releases/v2025.07

tutorial_packaging.rst

@@ -44,11 +44,20 @@ In order to avoid modifying your Spack installation with the package we are crea
 
 Doing this ensures changes we make here do not adversely affect other parts of the tutorial.
 
-Now let's look at the available repositories to us using the `spack repo list` command:
+Now let's look at the available repositories using ``spack repo list``:
 
 .. literalinclude:: outputs/packaging/repo-list.out
    :language: console
 
+Notice we now have two repositories: ``tutorial`` and ``builtin``.
+
+We can see how they are configured using ``spack config get repos``:
+
+.. literalinclude:: outputs/packaging/repo-config.out
+   :language: console
+
+Notice the default ``builtin`` repository is checked out at the latest release branch.
+
 You can find out more about repositories at `Package Repositories <https://spack.readthedocs.io/en/latest/repositories.html>`_ and the command at `spack repo <https://spack.readthedocs.io/en/latest/repositories.html#cmd-spack-repo>`_.