Add CoreNovus community banner asset; fix install code fence

Adds docs/assets/corenovus-community-banner.png (referenced by the README
header) and corrects the stray closing backtick on the pip-install fence.

Signed-off-by: Joel <yhocotw31016@example.com>

Author: Joel

README.md

@@ -34,7 +34,7 @@ Convilyn is for:
 
 ```bash
 pip install convilyn
-````
+```
 
 ## Quickstart