Fix incorrect HTML tag in README asterisk note

Author: robertpiosik

README.md

@@ -14,7 +14,7 @@
 
 Code Web Chat is a free and open-source AI coding toolkit. You can use CWC in **VS Code** family of editors (Cursor, Antigravity, VSCodium etc.) for a **much faster and cost efficient\*** development experience.
 
-<sup>\* A single prompt with the right context and simple instructions <i>is all you need!</i></sub>
+\* A single prompt with the right context and simple instructions <i>is all you need!</i>
 
 ✍️ **Construct coding prompts for...**