cask2formula: fix commit ID detection

cask2formula

@@ -190,9 +190,9 @@ class CaskConverter
       `git diff --name-only; git ls-files --others --exclude-standard`.split(/\s+/).each do |file|
           if file != "homebrew-cask-fonts" then
             shard_letter = File.basename(file).delete_prefix("font-")[0]
-            remote_dir = "homebrew-cask/blob/master/Casks/font/font-#{shard_letter}"
-            remote_source = "https://github.com/Homebrew/#{file.sub(/Formula/, remote_dir)}"
-            commit_id = `git -C homebrew-cask-fonts log -n 1 --pretty=format:%H -- #{file.sub(/Formula/, 'Casks')}`
+            remote_file = file.sub(/Formula/, "Casks/font/font-#{shard_letter}")
+            remote_source = "https://github.com/Homebrew/homebrew-cask/blob/master/#{remote_file}"
+            commit_id = `git -C homebrew-cask-fonts log -n 1 --pretty=format:%H -- #{remote_file}`
             system 'git', 'add', file
             system 'git', 'commit', '-m', "import #{remote_source} from #{commit_id}"
           end