Add github URLs for mentions

Signed-off-by: ahuston-0 <aliceghuston@gmail.com>

docs/CONTRIBUTING.md

@@ -101,7 +101,9 @@ rules.
 We allow secrets to be embedded in the repository using `sops-nix`. As part of
 the process everything is encrypted, however adding a new user is a change
 that every existing SOPS user needs to participate in. Please reach out to
-@ahuston-0, @DerDennnisOP, or @RichieCahill if you are interested
+[@ahuston-0](https://github.com/ahuston-0),
+[@DerDennisOP](https://github.com/DerDennisOp),or
+[@RichieCahill](https://github.com/RichieCahill) if you are interested
 in using secrets on your machines.
 
 ## CI/CD