refactor(specs-brew): add more information on format of tap arguments

Author: Wyatt-Stanke

specs/brew/homebrew_tap_repository.yaml

@@ -6,7 +6,7 @@ tags:
 description: Taps a Homebrew formula repository (a repository that contains Homebrew formulae) from GitHub.
 arguments:
   - name: tap_repository
-    description: The repository to tap
+    description: The repository to tap (in format of "username/repo")
     default_value: ~
 source_url: "https://docs.brew.sh/Manpage"
 author: Wyatt-Stanke