Correct grammar in README.md for welcoming contributions

Author: Peiyang-Song

README.md

@@ -177,7 +177,7 @@ theorem mul_left_comm : ∀ a b c : G, a * (b * c) = b * (a * c)
 
 * For general questions and discussions, please use [GitHub Discussions](https://github.com/lean-dojo/LeanCopilot/discussions).  
 * To report a potential bug, please open an issue. In the issue, please include your OS information, the exact steps to reproduce the error on **the latest stable version of Lean Copilot**, and complete logs preferrably in debug mode. **Important: If your issue cannot be reproduced easily, it will be unlikely to receive help.**
-* Feature requests and contributions are warmly welcomed. Please feel free to start a [discussion](https://github.com/lean-dojo/LeanCopilot/discussions) or open a [pull request](https://github.com/lean-dojo/LeanCopilot/pulls).
+* Feature requests and contributions are warmly welcome. Please feel free to start a [discussion](https://github.com/lean-dojo/LeanCopilot/discussions) or open a [pull request](https://github.com/lean-dojo/LeanCopilot/pulls).
 
 ## Acknowledgements