Use a code block for denoting directory structure

docs/html/reference/pip_install.rst

@@ -384,16 +384,14 @@ where ``setup.py`` is not in the root of project, the "subdirectory" component
 is used. The value of the "subdirectory" component should be a path starting
 from the root of the project to where ``setup.py`` is located.
 
-So if your repository layout is:
+So if your repository layout is::
 
-    - pkg_dir/
-
-      - setup.py  # setup.py for package ``pkg``
-      - some_module.py
-    - other_dir/
-
-      - some_file
-    - some_other_file
+   pkg_dir
+   ├── setup.py  # setup.py for package "pkg"
+   └── some_module.py
+   other_dir
+   └── some_file
+   some_other_file
 
 You'll need to use ``pip install -e "vcs+protocol://repo_url/#egg=pkg&subdirectory=pkg_dir"``.