Fix the sample module names

Author: y-taka-23

samples/Gists/StarGist.hs

@@ -1,5 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
-module StarRepo where
+module StarGist where
 
 import qualified GitHub.Data.Name       as N
 import qualified GitHub.Endpoints.Gists as GH

samples/Gists/UnstarGist.hs

@@ -1,5 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
-module StarRepo where
+module UnstarGist where
 
 import qualified GitHub.Data.Name       as N
 import qualified GitHub.Endpoints.Gists as GH