docs(git): Add configuration section

docs/git/index.rst

@@ -1,6 +1,38 @@
 Git
 ===
 
+Configuration
+-------------
+
+We recommend using:
+
+.. code-block:: bash
+
+   git config --global init.defaultBranch main
+   git config --global push.autoSetupRemote true
+   git config --global merge.conflictstyle zdiff3
+   git config --global diff.algorithm histogram
+   git config --global diff.colorMoved default
+   git config --global diff.colorMovedWS allow-indentation-change
+
+You might also like (requires installing `difftastic <https://difftastic.wilfred.me.uk/installation.html>`__):
+
+.. code-block:: bash
+
+   git config --global diff.tool difftastic
+
+If you sign commits, `tell Git about your signing key <https://docs.github.com/en/authentication/managing-commit-signature-verification/telling-git-about-your-signing-key>`__, for example:
+
+.. code-block:: bash
+
+   git config --global user.signingkey 3AA5C34371567BD2
+   git config --global commit.gpgsign true
+   git config --global gpg.program $(which gpg)
+
+.. seealso::
+
+   `Popular git config options <https://jvns.ca/blog/2024/02/16/popular-git-config-options/>`__
+
 Commit messages
 ---------------