doc:fix

Author: cunla

mkdocs.yml

@@ -30,7 +30,7 @@ markdown_extensions:
   - pymdownx.caret
   - pymdownx.details
   - pymdownx.emoji:
-      emoji_generator: !!python/name:materialx.emoji.to_svg
+      emoji_generator: !!python/name:material.extensions.emoji.to_svg
       emoji_index: !!python/name:material.extensions.emoji.twemoji
   - pymdownx.highlight:
       anchor_linenums: true