Move reversing_urls.rst into a subdirectory with it's own index, and include that index in the modeladmin docs' main toctree

docs/reference/contrib/modeladmin/index.rst

@@ -48,6 +48,7 @@ Want to know more about customising ``ModelAdmin``?
     create_edit_delete_views
     inspectview
     chooseparentview
+    tips_and_tricks/index
 
 .. _modeladmin_usage:
 
@@ -222,10 +223,3 @@ the same ``wagtail_hooks.py`` file if you want. The example below will create
     modeladmin_register(BookAdmin)
     modeladmin_register(MovieAdmin)
     modeladmin_register(MusicAdminGroup)
-
-
--------------------------
-Additional Tips & Tricks
--------------------------
-
-* To programatically generate URLs for any of your ``ModelAdmin`` views, see :ref:`modeladmin_reversing_urls`.

docs/reference/contrib/modeladmin/tips_and_tricks/index.rst

@@ -0,0 +1,10 @@
+==========================
+Additional tips and tricks
+==========================
+
+This section explores some of modeladmin's lesser-known features, and provides examples to help with modeladmin customisation. More pages will be added in future.
+
+.. toctree::
+    :maxdepth: 1
+
+    reversing_urls