docs: try to fix cannot find module 'material.extensions.emoji' (No m…

…odule named 'material')

[skip ci]

.readthedocs.yaml

@@ -16,6 +16,8 @@ build:
       - poetry config virtualenvs.create false
     post_install:
       - poetry install --with docs
+  commands:
+    - mkdocs build --clean --site-dir $READTHEDOCS_OUTPUT/html --config-file mkdocs.yml
 
 mkdocs:
   configuration: mkdocs.yml