Update emoji references

Author: effigies

mkdocs.yml

@@ -46,8 +46,8 @@ markdown_extensions:
   - toc:
       permalink: true
   - pymdownx.emoji:
-      emoji_index: !!python/name:materialx.emoji.twemoji
-      emoji_generator: !!python/name:materialx.emoji.to_svg
+      emoji_index: !!python/name:material.extensions.emoji.twemoji
+      emoji_generator: !!python/name:material.extensions.emoji.to_svg
   - pymdownx.tabbed
   - pymdownx.highlight
   - pymdownx.superfences