docs: restore CPython nav link

Keep the top navbar at 10 items (only License stays dropped). CPython (the
CPython-vs-MicroPython difference tables) returns alongside Language/Internals.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: kwagyeman

docs/conf.py

@@ -557,6 +557,7 @@ def _render_landing_code(src):
         {"title": "Shields", "url": "openmvcam/shields"},
         {"title": "Sensors", "url": "openmvcam/sensors"},
         {"title": "Language", "url": "reference/index"},
+        {"title": "CPython", "url": "genrst/index"},
         {"title": "Internals", "url": "develop/index"},
         {"title": "Changelog", "url": "changelog/index"},
     ],