Added new feature doc on configuring a custom theme

Author: tleonhardt

docs/features/index.md

@@ -27,6 +27,7 @@
 - [Shortcuts, Aliases, and Macros](shortcuts_aliases_macros.md)
 - [Startup Commands](startup_commands.md)
 - [Table Creation](table_creation.md)
+- [Theme](theme.md)
 - [Transcripts](transcripts.md)
 <!--intro-end-->
 </div>

docs/features/theme.md

@@ -0,0 +1,10 @@
+# Theme
+
+`cmd2` provides the ability to configure an overall theme for your application using the
+[cmd2.rich_utils.set_theme][] function. This is based o the
+[rich.theme](https://rich.readthedocs.io/en/stable/reference/theme.html) container for style
+information. You can use this to brand your application and set an overall consistent look and feel
+that is appealing to your user base.
+
+See [rich_theme.py](https://github.com/python-cmd2/cmd2/blob/main/examples/rich_theme.py) for a
+simple example of configuring a custom theme for your `cmd2` application.

mkdocs.yml

@@ -186,6 +186,7 @@ nav:
       - features/shortcuts_aliases_macros.md
       - features/startup_commands.md
       - features/table_creation.md
+      - features/theme.md
       - features/transcripts.md
   - Examples:
       - examples/index.md