Fixed warning about emoji logic (#9)

change should get rid of deprecation warning that "Material emoji
logic has been officially moved into mkdocs-material".

mkdocs.yml

@@ -72,8 +72,8 @@ markdown_extensions:
       smart_enable: all
   - pymdownx.details
   - pymdownx.emoji:
-      emoji_generator: !!python/name:materialx.emoji.to_svg
-      emoji_index: !!python/name:materialx.emoji.twemoji
+      emoji_generator: !!python/name:material.extensions.emoji.to_svg
+      emoji_index: !!python/name:material.extensions.emoji.twemoji
   - pymdownx.highlight:
       anchor_linenums: true
   - pymdownx.keys