Fix Markdown() documentation
diff --git a/rich/markdown.py b/rich/markdown.py
index 26167286b..35ac28c1c 100644
--- a/rich/markdown.py
+++ b/rich/markdown.py
@@ -399,7 +399,7 @@ class Markdown(JupyterMixin):
         style (Union[str, Style], optional): Optional style to apply to markdown.
         hyperlinks (bool, optional): Enable hyperlinks. Defaults to ``True``.
         inline_code_lexer: (str, optional): Lexer to use if inline code highlighting is
-            enabled. Defaults to "python".
+            enabled. Defaults to None.
         inline_code_theme: (Optional[str], optional): Pygments theme for inline code
             highlighting, or None for no highlighting. Defaults to None.
     """

Quick fix for #1350

## Type of changes

- [ ] Bug fix
- [ ] New feature
- [x] Documentation / docstrings
- [ ] Tests
- [ ] Other

## Checklist

- [ ] I've run the latest [black](https://github.com/psf/black) with default args on new code.
- [ ] I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
- [ ] I've added tests for new code.
- [x] I accept that @willmcgugan may be pedantic in the code review.

## Description

No real code added, just a fix in the docs as pointed out in #1350