Add a helpful snippet for using Hatch from Emacs

docs/how-to/integrate/emacs.md

@@ -0,0 +1,26 @@
+# How to use Hatch environments from Emacs
+
+-----
+
+The [pyvenv](https://github.com/jorgenschaefer/pyvenv) package is
+frequently used to manage virtual environments in Emacs (with
+[elpy](https://github.com/jorgenschaefer/elpy) for instance).  To make
+it easier to use with Hatch, you can add the following function to
+your `.emacs` to add the command `hatch-activate`, which works like
+`pyvenv-activate` but activates the default environment for the
+current directory:
+
+```lisp
+(require 'subr-x)
+(require 'pyvenv)
+(defun hatch-activate (directory)
+  "Activate the default hatch virtual environment for DIRECTORY"
+  (interactive (list (read-directory-name "Activate for project: ")))
+  (let ((expdir (expand-file-name directory))
+        (default-directory directory))
+    (let ((hatch-env
+           (string-trim
+            (shell-command-to-string "hatch env find"))))
+      (pyvenv-activate hatch-env)
+    )))
+```

mkdocs.yml

@@ -123,6 +123,7 @@ nav:
       - Report issues: how-to/meta/report-issues.md
     - Integrate:
       - Visual Studio Code: how-to/integrate/vscode.md
+      - Emacs: how-to/integrate/emacs.md
     - Run:
       - Python scripts: how-to/run/python-scripts.md
     - Config: