docs: remove ogp_description_length

WARNING: The config value 'ogp_description_length' has type 'str', defaults to 'int'.

Author: tony

docs/conf.py

@@ -117,7 +117,6 @@
 # sphinxext.opengraph
 ogp_site_url = about["__docs__"]
 ogp_image = "_static/img/icons/icon-192x192.png"
-ogp_description_length = about["__description__"]
 ogp_site_name = about["__title__"]
 
 # sphinx-copybutton