Link Fuzz Testing item to fuzz-testing section

Author: BowTiedRadone

guides-and-tutorials/testing-smart-contracts/README.md

@@ -5,7 +5,7 @@ thoroughly.
 
 This section covers testing Clarity contracts.
 
-- **Fuzz Testing**: Use Rendezvous to hammer your contract with random
+* [Fuzz Testing](./fuzz-testing.md): Use Rendezvous to hammer your contract with random
   inputs. It helps expose edge cases and vulnerabilities.
 
 More guides will follow.