Fix compatibility with click 8.3.0+

click 8.3.0 replaced None with a Sentinel.UNSET object for unset
parameter defaults. Use to_info_dict() which normalizes UNSET to
None across all supported click versions.

Author: stratakis

mkdocs_click/_docs.py

@@ -332,7 +332,8 @@ def _format_table_option_row(option: click.Option) -> str:
 
     # -> `False`
     none_default_msg = "_required" if option.required else "None"
-    default = f"`{option.default}`" if option.default is not None else none_default_msg
+    default_value = option.to_info_dict().get("default")
+    default = f"`{default_value}`" if default_value is not None else none_default_msg
 
     # -> "| `-V`, `--version` / `--show-version` | boolean | Show version info. | `False` |"
     return f"| {names} | {value_type} | {description} | {default} |"