docs: formatting on contribution

Author: krisk

CONTRIBUTING.md

@@ -76,7 +76,7 @@ Before you submit your pull request consider the following guidelines:
 
 That's it! Thank you for your contribution!
 
-#### After your pull request is merged
+### After your pull request is merged
 
 After your pull request is merged, you can safely delete your branch and pull the changes
 from the main (upstream) repository: