Update .github/CONTRIBUTING.md

Co-authored-by: Mark Wiemer <[email protected]>

Author: hainenber

.github/CONTRIBUTING.md

@@ -39,7 +39,7 @@ Most importantly:
 - Include your test code or file(s).
   If large, please provide a link to a repository or [gist](https://gist.github.com).
 
-We'll discuss your proposed changes and how they relate to the overarching goals of Mocha, detailed below in [⚽️ About Project Goals](#️-about-project-goals).
+We'll discuss your proposed changes and how they relate to the overarching goals of Mocha, detailed below in [⚽️ About Project Goals](#%EF%B8%8F-about-project-goals).
 
 ## ⚽️ About Project Goals